Metal member, implant member, and metal member for living body

Abstract

Provided is a metal member containing at least 98.8 mass% of titanium, wherein: the metal member includes a first region and a second region; the first region is a region in which the distance from the surface of the metal member is 3 μm or less and the contained amount of alpha titanium having an alpha-phase crystal structure is at least 10 vol%; the second region is a region in which the distance from the surface of the metal member is at least 40 μm; the amount of omega titanium having an omega-phase crystal structure contained in the second region is at least 95 vol%; the metal member contains 0.1-2.0 vol% of first particles; and in a spectrum obtained by performing elemental analysis on the first particles using an energy dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is 0.5 or above.

Description

Metal components, implant components, and biocompatible metal components

[0001] This disclosure relates to metal components, implant components, and biomedical metal components.

[0002] Titanium has been used in fields such as the aerospace and automotive industries due to its high specific strength. Furthermore, its excellent biocompatibility has led to increasing demand for it as a biocompatible metal material, such as in dental implants.

[0003] The titanium that makes up currently widely used titanium materials is alpha-titanium, which has an alpha-phase crystal structure. Alpha-pure titanium, which has a high alpha-titanium content, has high elongation at break (hereinafter also referred to as ductility), but low tensile strength (hereinafter also referred to as strength). On the other hand, titanium alloys in which other metals are added to titanium have high tensile strength, but low elongation at break. Thus, in conventional titanium materials mainly composed of alpha-titanium, there is a trade-off relationship between strength and ductility, and it has not been possible to obtain a titanium material that can achieve both high strength and high ductility.

[0004] Patent Document 1 discloses that a titanium material containing omega titanium having an omega phase crystal structure can achieve both high strength and high ductility.

[0005] International Publication No. 2023 / 100603

[0006] The metal member of this disclosure is a metal member containing 98.8% by mass or more of titanium, wherein the metal member comprises a first region and a second region, the first region being a region within 3 μm of the surface of the metal member and having an alpha-phase crystal structure with a content of 10% by volume or more of alpha titanium, the second region being a region being 40 μm or more of the surface of the metal member, the content of omega-titanium having an omega-phase crystal structure in the second region being 95% by volume or more, the metal member containing 0.1% by volume or more and 2.0% by volume or less of first particles, and in a spectrum obtained by elemental analysis of the first particles using an energy-dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is 0.5 or more.

[0007] Figure 1 is a schematic cross-sectional view of the metal member of Embodiment 1. Figure 2 is a schematic cross-sectional view of the high-pressure cell of the ultra-high-pressure, high-temperature generating device used in the manufacture of the metal member of Embodiment 1. Figure 3 is a schematic diagram showing the basic structure of an implant using the implant member of Embodiment 2. Figure 4 is a backscattered electron image of the metal member of sample 35. Figure 5 is a backscattered electron image of the titanium material of sample 105.

[0008] [Problems this disclosure aims to solve] According to Patent Document 1, the higher the omega titanium content of a titanium material, the better the strength and ductility. Therefore, from the viewpoint of improving strength and ductility, it is presumed that increasing the omega titanium content of the titanium material is effective.

[0009] On the other hand, alpha-titanium has a longer track record of use than omega-titanium, and there is abundant information available regarding surface treatment methods and biocompatibility. From the perspective of ease of surface treatment and safety when used as a biomaterial, the presence of alpha-titanium on the surface of titanium material is required.

[0010] Therefore, the present disclosure aims to provide a metal component, implant component, and biomedical component that has a higher omega titanium content than conventional titanium materials mainly composed of alpha titanium, and that also contains alpha titanium on its surface.

[0011] [Effects of this disclosure] According to this disclosure, it is possible to provide metal members, implant members, and biomedical metal members that have a higher omega titanium content than conventional titanium materials mainly composed of alpha titanium, and that also contain alpha titanium on their surface.

[0012] [Description of Embodiments of the Disclosure] Embodiments of the Disclosure will be described first by listing them. (1) The metal member of the Disclosure is a metal member containing 98.8% by mass or more of titanium, wherein the metal member includes a first region and a second region, wherein the first region is a region within 3 μm of the surface of the metal member and has a content of 10% by volume or more of alpha titanium having an alpha phase crystal structure, the second region is a region within 40 μm of the surface of the metal member, the content of omega titanium having an omega phase crystal structure in the second region is 95% by volume or more, the metal member contains 0.1% by volume or more and 2.0% by volume or less of first particles, and in a spectrum obtained by performing elemental analysis on the first particles using an energy-dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is 0.5 or more.

[0013] According to this disclosure, it is possible to provide a metal component that has a higher omega titanium content than conventional titanium materials mainly composed of alpha titanium, and that also contains alpha titanium on its surface.

[0014] The metal member of this disclosure contains a first particle. The presence of the first particle in the metal member allows the metal member to have high strength due to the precipitation strengthening effect. In this disclosure, "the metal member has high strength" means that the strength of the metal member of this disclosure is higher than the strength of conventional titanium materials with the same titanium content and in which the titanium is alpha titanium. In this disclosure, "strength" means tensile strength.

[0015] (2) In (1) above, the titanium consists of a plurality of titanium particles, and at least one of the first particles may be present at the grain boundary of the titanium particles. This further improves the strength of the metal member. This is presumed to be because the first particle is present at the grain boundary of the titanium particles, making it easier to obtain the effect of precipitation strengthening.

[0016] (3) In (1) or (2) above, the alpha titanium content in at least a portion of the first region may be 10% by volume or more and less than 50% by volume. In this case, at least a portion of the surface of the metal member can have excellent strength, and the metal member can be suitably used in applications where strength is particularly required.

[0017] (4) In (1) or (2) above, the alpha titanium content in at least a part of the first region may be 50% by volume or more and 100% by volume or less. According to this, since the alpha titanium content is high in at least a part of the surface of the metal member, existing surface treatment methods can be easily applied to the metal member, and the reliability regarding the biocompatibility of the metal member is high.

[0018] (5) In any of (1) to (4) above, the standard deviation of the alpha titanium content in at least a part of the first region may be 1.5 volume percent or more. According to this, on the surface of the same metal member, regions with a high alpha titanium content and regions with a low alpha titanium content can coexist depending on the application.

[0019] (6) In any of (1) to (5) above, the average particle size of the first particles may be 5 nm or more and 100 nm or less. This further improves the strength of the metal component. This is presumed to be because the first particles are dispersed, making it easier to obtain the effect of precipitation strengthening.

[0020] (7) In any of (1) to (6) above, in the first image obtained by binarizing the backscattered electron image obtained by observing the cross section of the metal member at 10,000x magnification using the scanning electron microscope, the number of first particles per unit area is 10 particles / 25 μm ２More than 100 pieces / 25μm ２ The following is also acceptable.

[0021] According to this, the strength of the metal component is further improved. This is presumed to be because the first particles are dispersed, making it easier to obtain the precipitation strengthening effect.

[0022] (8) The implant member of the present disclosure is an implant member made of a metal member as described in any of (1) to (7) above.

[0023] The implant member of this disclosure has a higher omega titanium content than conventional implant members made of titanium material mainly composed of alpha titanium, and can therefore have superior strength and ductility. Furthermore, because the implant member contains alpha titanium on its surface, it is easy to surface treat and has excellent biocompatibility.

[0024] (9) The biomedical metal component of the present disclosure is a biomedical metal component comprising the metal component described in any of (1) to (7) above.

[0025] The bio-metal components disclosed herein have a higher omega-titanium content than conventional bio-metal components made of titanium material mainly composed of alpha-titanium, and can therefore possess superior strength and ductility. Furthermore, because the bio-metal components contain alpha-titanium on their surface, they offer superior ease of surface treatment and safety for living organisms.

[0026] (10) In (9) above, the bio-metal member may be an artificial skull fixation member, a spinal device fixation member, a component of an implantable device, or a component of a sensor housing.

[0027] (11) In (10) above, the artificial skull fixing member or the spinal device fixing member may be a rod, a plate, or a screw.

[0028] [Details of Embodiments of the Disclosure] Specific examples of the metal members, implant members, and biomedical metal members of the Disclosure will be described below with reference to the drawings. In the drawings of the Disclosure, the same reference numerals represent the same part or a corresponding part. In addition, dimensional relationships such as length, width, thickness, and depth have been appropriately modified for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0029] In this disclosure, the notation "A to B" means A or greater and B or less. If no unit is specified for A, and only a unit is specified for B, then the unit for A and the unit for B are the same.

[0030] In this disclosure, if one or more numerical values ​​are listed as the lower limit and upper limit of a numerical range, any combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit shall also be disclosed.

[0031] In this disclosure, “equipment,” “includes,” “possesses,” and variations thereof are open-ended terms. Open-ended terms may or may not include additional elements in addition to the essential elements. The statement “consists of” is a closed term. However, even a configuration expressed in closed terms may include additional elements that are usually incidental or irrelevant to the subject technology.

[0032] In this disclosure, unless otherwise specified, it has been confirmed that measurements taken with a defined measurement field or measurement area show little variation in the measured values, even when the position of the measurement field or measurement area is changed, as long as the same sample is being measured.

[0033] [Embodiment 1: Metal Member] A metal member according to an embodiment of the present disclosure (hereinafter also referred to as "Embodiment 1") will be described with reference to FIG. 1. The metal member 20 contains 98.8 mass% or more of titanium. The metal member 20 includes a first region 21 and a second region 22. The first region 21 is a region where the distance from the surface 23 of the metal member 20 is within 3 μm and the content rate of alpha titanium having a crystal structure of the alpha phase is 10% by volume or more. The second region 22 is a region where the distance from the surface 23 of the metal member 20 is 40 μm or more, and the content rate of omega titanium having a crystal structure of the omega phase in the second region 22 is 95% by volume or more. The metal member 20 contains 0.1% by volume or more and 2.0% by volume or less of first particles. In the spectrum obtained by performing elemental analysis on the first particles using an energy dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is 0.5 or more.

[0034] <Titanium Content Rate> The metal member of Embodiment 1 contains 98.8 mass% or more of titanium. Thereby, the metal member has high specific strength and excellent biocompatibility. The titanium content rate of the metal member may be 98.8 mass% or more and 100 mass% or less, may be 98.9 mass% or more and 100 mass% or less, may be 99.0 mass% or more and 99.99 mass% or less, may be 99.2 mass% or more and 99.99 mass% or less, may be 99.3 mass% or more and 99.99 mass% or less, or may be 99.4 mass% or more and 99.99 mass% or less.

[0035] The metal member of Embodiment 1 can be composed of titanium and other components other than titanium. The other components can be composed of at least one selected from the group consisting of general transition metal elements (scandium (Sc), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), silver (Ag), hafnium (Hf), tantalum (Ta), tungsten (W), platinum (Pt), gold (Au), etc.), and hydrogen (H), carbon (C), nitrogen (N), and oxygen (O) as inevitable impurities.

[0036] In the case where the other components of the metal member of Embodiment 1 are transition metal elements, the content rate of the other components is measured by high-frequency inductively coupled plasma (ICP: Inductively Coupled Plasma) emission spectrometry. In the case where the other components are elements other than transition metal elements such as hydrogen, carbon, nitrogen, and oxygen, the content rate is measured by secondary ion mass spectrometry (SIMS: Secondary Ion Mass Spectrometry).

[0037] The content rate of titanium in the metal member is obtained by measuring the content rate of components other than titanium by the above method, taking the metal member as 100% by mass, and then subtracting the content rate of components other than titanium therefrom.

[0038] <Metal member configuration> As shown in FIG. 1, the metal member 20 of Embodiment 1 includes a first region 21 and a second region 22.

[0039] <<First region>> In the metal member 20 of Embodiment 1, the first region 21 is a region where the distance from the surface 23 of the metal member 20 is within 3 μm and the content rate of alpha titanium having a crystal structure of the alpha phase is 10% by volume or more. Here, the region where the distance from the surface 23 of the metal member 20 is within 3 μm can also be expressed as the region sandwiched between the surface 23 of the metal member 20 and a virtual plane L1 whose distance from the surface 30 of the metal member 20 to the inside of the metal member is 3 μm. In FIG. 1, the entire surface of the metal member 20 is constituted by the first region 21, but the first region 21 may constitute a part of the surface of the metal member 20.

[0040] In the metal member of Embodiment 1, the content rate of alpha titanium in the first region is 10% by volume or more, may be 10% by volume or more and 100% by volume or less, may be 20% by volume or more and 100% by volume or less, may be 40% by volume or more and 100% by volume or less, may be 60% by volume or more and 100% by volume or less, may be 80% by volume or more and 100% by volume or less, or may be 100% by volume.

[0041] In the present disclosure, the method for confirming that the metal member includes the first region is as follows.

[0042] Procedure A1. The surface of the metal component is observed using a micro-X-ray diffractometer (Rigaku Corporation's "SmartLab" trademark) to identify the region where alpha titanium is present. The measurement conditions are as follows: X-ray used: Cu-Ka, excitation conditions: 45kV, 200mA, incident slit size: 0.8mm × vertical 0.1mm, detector: HyPix-3000 (2D), scanning method: 2θ-θ scan, measurement range: 2θ = 25°-90°, step width: 0.03°, scan speed: 0.5° / min. The region where diffraction peaks are observed in the range of 2θ = 39.7°-40.4° is determined to be the region where alpha titanium is present.

[0043] The metal component is cut along the normal to the surface region where alpha titanium is present, exposing the cross-section. If the surface region does not have a planar area, the cross-section is exposed by cutting from any point on the surface region along the direction toward the center of gravity of the metal component. The cross-section is then polished to a mirror finish using a cross-section polisher (manufactured by JEOL Ltd.).

[0044] Procedure B1. Observe the mirror-finished cross-section of the metal component using an electron backscatter diffractometer (SEM-EBSD; SEM: Carl Zeiss "Gemini 450" (trademark), EBSD: Oxford "Symmetry" (trademark)) attached to a scanning electron microscope. The observation magnification should be 1000 to 10000x. The measurement conditions should be an acceleration voltage of 15kV, a current of 15nA, and a step size of 0.1 to 0.02μm / step. Perform EBSD analysis on the obtained observation image.

[0045] Procedure C1. The EBSD analysis results are subjected to phase analysis using commercially available software (Oxford's "AZtecCrystal" trademark) to obtain a phase mapping image showing the crystalline structure of titanium. The crystalline structure of titanium identified here is the crystalline structure observed when viewing the titanium appearing in the cross-section of the metal component from a plan view in the direction normal to the cross-section.

[0046] Procedure D1. In the phase mapping image, a rectangular measurement area of ​​3 μm × 8 μm is set within the region sandwiched between the surface 23 of the metal member and a virtual line L1, the distance from the surface 23 to the interior of the metal member 20 being 3 μm. The measurement area has a length of 3 μm in the depth direction and a length of 8 μm in the direction perpendicular to the depth direction. If the surface of the metal member is uneven, in the phase mapping image, the line that passes through the position of the metal member's surface that protrudes furthest inward and is perpendicular to the depth direction is considered to be the surface of the metal member. In this disclosure, the depth direction is the direction perpendicular to the average line of the metal member's surface as defined in JIS B 0601-1994 in the phase mapping image. The region sandwiched between the surface of the metal member and the virtual line L1 in the phase mapping image corresponds to the region of the metal member within a distance of 3 μm from the surface of the metal member.

[0047] Procedure E1. Using the software described above, measure the percentage of the alpha-titanium area relative to the total area of ​​the measurement region (hereinafter also referred to as "alpha-titanium area percentage").

[0048] Procedure F1. The area percentage of alpha titanium described above is measured in multiple non-overlapping measurement regions. The multiple measurement regions may be located on the same cross-section of the metal member, or they may be located on different cross-sections. In this disclosure, if there are five or more measurement regions in which the area percentage of alpha titanium is 10 volume% or more, it is confirmed that the metal member includes a first region within 3 μm of the surface of the metal member, and in which the content of alpha titanium having an alpha phase crystal structure is 10 volume% or more.

[0049] In this disclosure, as described in procedure F1, a metal member is determined to include the first region if there are five or more measurement regions on the same cross-section of the metal member (hereinafter also referred to as the "first cross-section") in which the area percentage of alpha titanium is 10 volume percent or more. In this case, it can be confirmed that the first region also exists in a direction perpendicular to the first cross-section by the following procedure: The metal member including the first cross-section is cut along the normal to the first cross-section so as to pass through the first region within the first cross-section, exposing the second cross-section. In the second cross-section, the alpha titanium content in the measurement regions is measured in the same manner as in procedures A1 to F1 above. If the second cross-section includes five or more measurement regions in which the alpha titanium content is 10 volume percent or more, it is confirmed that the first region also exists in a direction perpendicular to the first cross-section.

[0050] Furthermore, in the same metal component, in the region where alpha-titanium is present and the results observed with a micro-X-ray diffractometer in procedure A1 are almost identical, it has been confirmed that the alpha-titanium content of the first region is almost identical in multiple different cross-sections obtained by cutting along the normal to the region. This indicates that the first region extends in the in-plane direction on the surface of the metal component.

[0051] In this disclosure, if the above verification method confirms that the metal member includes the first region, it is determined that the surface of the metal member includes a region in which the alpha-titanium content is 10 volume percent or more.

[0052] In the metal member of Embodiment 1, the first region may contain omega titanium along with alpha titanium. The total content of alpha titanium and omega titanium in the first region may be 95% by volume or more, 98% by volume or more, 99% by volume or more, or 100% by volume. The first region may also contain beta titanium, as long as it does not impair the effects of the present disclosure.

[0053] In this disclosure, the method for measuring the total content of alpha titanium and omega titanium in the first region is as follows: Ten measurement regions are identified in which the area percentage of alpha titanium is 10 volume% or more, based on the method for confirming that the above metal component includes the first region. In each measurement region, the sum of the percentage of alpha titanium area and the percentage of omega titanium area relative to the total area of ​​the measurement region is measured using the above software. The average of the sum of the percentages of alpha titanium area and omega titanium area for the ten measurement regions is calculated. In this disclosure, this average corresponds to the total content of alpha titanium and omega titanium in the first region.

[0054] In the metal member of Embodiment 1, the alpha-titanium content in at least a portion of the first region may be 10% by volume or more and less than 50% by volume, or 20% by volume or more and 40% by volume or less. As a result, since at least a portion of the surface of the metal member has an alpha-titanium content of less than 50% by volume, it is easy to ensure excellent strength, and it can be suitably used in applications where strength is particularly required. Examples of applications include implant members with a diameter of 2 mm or more and 4 mm or less. Such implant members are preferably used, for example, in anterior teeth.

[0055] In this disclosure, the method for confirming that the alpha-titanium content in at least a portion of the first region is 10% by volume or more and less than 50% by volume is as follows: The area percentage of alpha-titanium is measured in multiple measurement regions using the same method as the method for confirming that the metal member includes the first region. In this disclosure, if there are five or more measurement regions in which the area percentage of alpha-titanium is 10% by volume or more and less than 50% by volume, it is confirmed that the alpha-titanium content in at least a portion of the first region is 10% by volume or more and less than 50% by volume.

[0056] In this disclosure, if the above-described verification method confirms that the alpha-titanium content in at least a portion of the first region of the metal member is 10% by volume or more and less than 50% by volume, then the surface of the metal member is determined to include a region in which the alpha-titanium content is 10% by volume or more and less than 50% by volume.

[0057] In the metal member of Embodiment 1, the alpha-titanium content in at least a portion of the first region may be 50% by volume or more and 100% by volume or 60% by volume or more and 80% by volume. This allows for a high alpha-titanium content in at least a portion of the surface of the metal member, making it easier to apply existing surface treatment methods to the metal member and providing high reliability regarding the biocompatibility of the metal member. Examples of applications include implant members with a diameter of 3 mm or more. Such implant members are preferably used for intermediate teeth and molars, for example.

[0058] In this disclosure, the method for confirming that the alpha-titanium content in at least a portion of the first region is 50% by volume or more and 100% by volume or less is as follows: The area percentage of alpha-titanium is measured in multiple measurement regions using the same method as the method for confirming that the metal member includes the first region. In this disclosure, if there are five or more measurement regions in which the area percentage of alpha-titanium is 50% by volume or more and 100% by volume or less, it is confirmed that the alpha-titanium content in at least a portion of the first region is 50% by volume or more and 100% by volume or less.

[0059] In this disclosure, if the above-described verification method determines that the alpha-titanium content in at least a portion of the first region of the metal member is 50% by volume or more and 100% by volume or less, then the surface of the metal member is determined to include a region in which the alpha-titanium content is 50% by volume or more and 100% by volume or less.

[0060] In at least a portion of the first region of the metal member of Embodiment 1, the standard deviation of the alpha-titanium content may be 1.5% or more, 1.5% to 4%, 1.6% to 3%, or 1.7% to 2%. This indicates that there is variation in the alpha-titanium content in the first region. This allows for the coexistence of regions with high alpha-titanium content and regions with low alpha-titanium content on the surface of the same metal member, depending on the application.

[0061] In this disclosure, the method for measuring the standard deviation of the alpha-titanium content in at least a portion of the first region is as follows: The area percentage of alpha-titanium is measured in multiple measurement regions using the same method as the method for confirming that the metal member includes the first region. The multiple measurement regions are arranged so that the depth-direction edges of adjacent measurement regions are touching. Ten measurement regions are identified from the multiple measurement regions in which the area percentage of alpha-titanium is 10 volume percent or more and the depth-direction edges of adjacent measurement regions are touching. The ten measurement regions as a whole form a rectangle with dimensions of 3 μm (length in the depth direction) × 80 μm (length in the direction perpendicular to the depth direction). The standard deviation of the alpha-titanium content is calculated based on the alpha-titanium content of each of the ten measurement regions. In this disclosure, this standard deviation corresponds to the standard deviation of the alpha-titanium content in at least a portion of the first region.

[0062] In the first embodiment, the first region may constitute the entire surface or a part of the surface. The area of ​​the first region on the surface of the metal member can be appropriately set depending on the application of the metal member. The percentage of the area of ​​the first region to the total surface area of ​​the metal member may be, for example, 10% or more and 100%, 50% or more and 100%, or 60% or more and 80%.

[0063] ≪Second Region≫ In the metal member of Embodiment 1, the second region is a region that is 40 μm or more away from the surface of the metal member. Here, the region that is 40 μm or more away from the surface of the metal member can also be expressed as the internal region of the metal member that is 40 μm or more away from the surface of the metal member. The content of omega titanium having an omega phase crystal structure in the second region is 95 volume% or more, may be 95 volume% to 100 volume%, may be 98 volume% to 100 volume%, may be 99 volume% to 100 volume%, or may be 100 volume%.

[0064] In this disclosure, a method for measuring the omega titanium content of the second region will be described with reference to Figure 1.

[0065] Procedure A2. Obtain a phase mapping image of the cross-section of the metal member using the same method as in Procedures A1 to C1 above.

[0066] Procedure B2. In the phase mapping image, a rectangular measurement area of ​​3 μm × 8 μm is set within the region inside the virtual line L2, which is 40 μm from the surface 23 of the metal member 20 (the region below the virtual line L2 in Figure 1). If the surface of the metal member is uneven, in the phase mapping image, the line that passes through the position of the metal member's surface that protrudes furthest inward and is perpendicular to the depth direction is considered to be the surface of the metal member. The region inside the virtual line L2, which is 40 μm from the surface of the metal member in the phase mapping image, corresponds to the region of the metal member that is 40 μm or more from the surface.

[0067] Procedure C2. Using the software described above, measure the percentage of the area of ​​omega titanium relative to the total area of ​​the measurement region (hereinafter also referred to as "area percentage of omega titanium").

[0068] Procedure D2. The area percentage of omega titanium described above is measured in five non-overlapping measurement areas. The average of the area percentages of omega titanium in the five measurement areas is calculated. In this disclosure, this average corresponds to the omega titanium content of the second area.

[0069] In the metal member of Embodiment 1, the second region may contain alpha titanium along with omega titanium. The total content of alpha titanium and omega titanium in the first region may be greater than 95 vol%, 98 vol% or more, 99 vol% or more, or 100 vol%. The second region may also contain beta titanium, as long as it does not impair the effects of the present disclosure.

[0070] In this disclosure, the method for measuring the total content of alpha titanium and omega titanium in the second region is as follows: In each of the five measurement regions set out in the method for measuring the content of omega titanium in the second region described above, the total percentage of the area of ​​alpha titanium and the total percentage of the area of ​​omega titanium relative to the total area of ​​the measurement region is measured using the software described above. The average of the total percentages of the areas of alpha titanium and omega titanium in the five measurement regions is calculated. In this disclosure, this average corresponds to the total content of alpha titanium and omega titanium in the second region.

[0071] In the metal member of Embodiment 1, the average grain size of the crystal grains constituting the second region (hereinafter also referred to as "average grain size of the second region") may be 1 μm or more and 1000 μm or less. If the average grain size of the second region is 1 μm or more, the strength of the metal member is improved. If the average grain size of the second region is 1000 μm or less, the ductility of the metal member is improved.

[0072] The average particle size of the second region may be 3 μm or more and 500 μm or less, 5 μm or more and 200 μm or less, 10 μm or more and 100 μm or less, 10 μm or more and 50 μm or less, or 20 μm or more and 50 μm or less.

[0073] In this disclosure, the method for measuring the average particle size of the second region is as follows: The cross-section of the metal member is polished, and the polished surface is imaged at a magnification of 100x using an optical microscope to obtain an optical microscope image.

[0074] A 50 mm x 50 mm measurement field is set within the second region of the optical microscope image. The optical microscope image is processed using commercially available image analysis software to measure the equivalent circle diameter of each crystal grain within the measurement field, and the arithmetic mean of the equivalent circle diameters is calculated.

[0075] The above measurements are performed on a single sample in three non-overlapping measurement fields, and the arithmetic mean average of the equivalent circle diameters in the three measurement fields is calculated. In this disclosure, this average corresponds to the average particle size of the second region.

[0076] In the metal member of Embodiment 1, the grain size of the crystal grains constituting the second region is preferably small in variation from the viewpoint of homogenizing strength and ductility. The ratio D90 / D10 of the cumulative 90% particle size from the small diameter side to the cumulative 10% particle size D10 from the small diameter side in the volume-based cumulative particle size distribution of the crystal grains constituting the second region, which is D90 / D10, may be 5 or more and 1000 or less, or 10 or more and 1000 or less. A smaller value of D90 / D10 indicates smaller variation in the grain size of the crystal grains.

[0077] The measurement method for D90 / D10 described above is as follows: Using the same method as the measurement method for the average particle size of the second region described above, the equivalent circular diameter of all crystal grains observed in the measurement field is measured, and a volume-based cumulative particle size distribution is created based on this. D90 / D10 is calculated based on this cumulative particle size distribution.

[0078] <Other Regions> The metal member of Embodiment 1 includes other regions besides the first and second regions. These other regions include, for example, the region sandwiched between the first and second regions, and the region where the distance from the surface of the metal member to the interior of the metal member is within 3 μm and the alpha titanium content is less than 10 volume%. From a manufacturing standpoint, the omega titanium content of the other regions may be greater than or equal to the omega titanium content of the first region and less than or equal to the omega titanium content of the second region. This has been confirmed to ensure excellent strength and ductility of the metal member. The omega titanium content of the other regions may be, for example, 90 volume% or more, 93 volume% or more, 95 volume% or more, 98 volume% or more, 99 volume% or more, or 100 volume%.

[0079] In this disclosure, the method for measuring the omega titanium content in other regions is as follows:

[0080] Procedure A3. Obtain a phase mapping image of the cross-section of the metal member using the same method as in Procedures A1 to C1 above.

[0081] Procedure B3. In the phase mapping image, set a rectangular measurement area of ​​3 μm × 8 μm within the areas other than the first and second regions.

[0082] Procedure C3. Using the software described above, measure the percentage of the area of ​​omega titanium relative to the total area of ​​the measurement region (hereinafter also referred to as "area percentage of omega titanium").

[0083] Procedure D3. The area percentage of omega titanium described above is measured in five non-overlapping measurement areas. The average of the area percentages of omega titanium in the five measurement areas is calculated. In this disclosure, this average corresponds to the omega titanium content in the other areas.

[0084] In the metal member of Embodiment 1, the other regions may contain alpha titanium along with omega titanium. The total content of alpha titanium and omega titanium in the other regions may be greater than 95% by volume, 98% or more by volume, 99% or more by volume, or 100% by volume. The other regions may also contain beta titanium, as long as it does not impair the effects of the present disclosure.

[0085] In this disclosure, the method for measuring the total content of alpha titanium and omega titanium in other areas is as follows: In each of the five measurement areas set out in the method for measuring the content of omega titanium in other areas described above, the software described above is used to measure the sum of the percentage of alpha titanium area and the percentage of omega titanium area relative to the total area of ​​the measurement area. The average of the sum of the percentages of alpha titanium area and omega titanium area for the five measurement areas is calculated. In this disclosure, this average corresponds to the total content of alpha titanium and omega titanium in other areas.

[0086] <First Particles> <Content of First Particles> The metal member of Embodiment 1 contains first particles in an amount of 0.1 volume% to 2.0 volume%. When the content of first particles in the metal member is 0.1 volume% or more, the precipitation strengthening effect is improved. When the content of first particles in the metal member is 2.0 volume% or less, the elongation at break of the metal member is easily maintained. The content of first particles in the metal member may be 0.2 volume% to 1.8 volume%, 0.3 volume% to 1.5 volume%, or 0.8 volume% to 1.0 volume%.

[0087] In the metal member of Embodiment 1, the first particle may be present in one or both of the first and second regions.

[0088] In this disclosure, the first particle is defined as a particle in which, in a spectrum obtained by elemental analysis of the first particle using an energy-dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity derived from carbon to the maximum peak intensity derived from titanium C1 is 0.5 or greater. In this disclosure, the first particle is identified by the following procedure.

[0089] Procedure A4. Cut out a section of the metal component at an arbitrary location to expose the cross-section. Polish the cross-section to a mirror finish using a cross-section polisher (manufactured by JEOL Ltd.).

[0090] Procedure B4. The mirror-finished surface of the metal component is photographed with a scanning electron microscope (SEM) (ZEISS "Gemini 450" trademark) to obtain a backscattered electron image. A backscattered electron image is prepared that includes at least the first region, and another that includes at least the second region. The observation magnification is 10,000x. The measurement conditions are an acceleration voltage of 3kV, a current of 2nA, and a working distance (WD) of 5mm.

[0091] Procedure C4. The backscattered electron image obtained in Procedure B4 is imported into a computer and binarized using image analysis software (ImageJ Version 1.54d 30 March 2023). Note that the binarization threshold changes depending on the contrast, so it must be set for each image.

[0092] Procedure D4. Elemental analysis is performed on the region shown in black in the binarized image using an energy-dispersive X-ray spectrometer (SEM-EDS) attached to a scanning electron microscope to obtain a spectrum. In the spectrum, the X-axis represents energy (unit: keV), and the Y-axis represents X-ray intensity (unit: cps). In the obtained spectrum, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is calculated. The maximum peak derived from titanium is a peak located at an energy between 0.3 keV and 0.5 keV. The maximum peak derived from carbon is a peak located at an energy between 0.1 keV and 0.3 keV. In this disclosure, if the ratio C2 / C1 is 0.5 or greater, the region shown in black is determined to be the first particle. There is no particular upper limit to the ratio C2 / C1, but it can be, for example, 0.9 or less.

[0093] In this disclosure, the volume-based content of the first particle of the metal component is measured by the following procedure.

[0094] Procedure A5. Identify the first particle in the binarized image following the steps in Procedures A4 to D4.

[0095] Procedure B5. Set a single measurement field of view of 5 μm × 5 μm in the binarized image. Using the image analysis software described above, measure the area percentage of the first particle, with the area of ​​the entire measurement field of view as the denominator.

[0096] Procedure C5. Perform the measurement in Procedure B5 in six distinct, non-overlapping measurement fields. Of the six measurement fields, three measurement fields A are set to include at least the first region. Calculate the area percentage A of the first particles in each of the first regions of the three measurement fields A. The other three measurement fields B are set to include at least the second region. Calculate the area percentage B of the first particles in each of the second regions of the three measurement fields B. Calculate the average of the area percentage A of the first regions of the three measurement fields A and the area percentage B of the first regions of the three measurement fields B. In this disclosure, this average corresponds to the content (volume %) of the first particles in the metal member.

[0097] <<Average particle size of the first particles>> In the metal member of Embodiment 1, the average particle size of the first particles may be 5 nm or more and 120 nm or less, may be 5 nm or more and 100 nm or less, may be 5 nm or more and 50 nm or less, or may be 5 nm or more and 40 nm or less. When the average particle size of the first particles is particularly 100 nm or less, the strength of the metal member is likely to be improved. The lower limit of the average particle size of the first particles is set from the viewpoint of manufacturing. In the present disclosure, the average particle size of the first particles is measured by the following procedure.

[0098] Procedure A6. According to the procedures of Procedure A4 to Procedure D4, identify the first particles in the image after the binarization process.

[0099] Procedure B6. In the image after the binarization process, set one measurement field of a 5 μm × 5 μm rectangle. Using the above image analysis software, calculate the equivalent circle diameter of each of all the first particles in the measurement field. Calculate the arithmetic mean of the equivalent circle diameters of all the first particles in the measurement field (hereinafter also referred to as "the first average diameter of the first particles").

[0100] Procedure C6. Perform the measurement of Procedure B6 in six different non-overlapping measurement fields set at the same position as in Procedure C5. In the present disclosure, the arithmetic mean of the first average diameters of the first particles in the six measurement fields corresponds to the average particle size of the first particles.

[0101] <<Number per unit area of the first particles>> In the first image obtained by performing binarization processing on the backscattered electron image obtained by observing the cross section of the metal member of Embodiment 1 at a magnification of 10,000 times using a scanning electron microscope, the number per unit area of the first particles is 10 pieces / 25 μm ２ or more and 100 pieces / 25 μm ２ or less, may be 15 pieces / 25 μm ２ or more and 80 pieces / 25 μm ２ or less, or may be 20 pieces / 25 μm ２ or more and 50 pieces / 25 μm ２ or less. When the number per unit area of the first particles is 10 pieces / 25 μm ２ or more, the strength of the metal member is likely to be improved. When the number per unit area of the first particles is 100 pieces / 25 μm ２The following conditions can suppress the reduction in elongation at break and the resulting increased susceptibility to fracture. In this disclosure, the number of first particles per unit area is measured by the following procedure.

[0102] Procedure A7. Identify the first particle in the binarized image following the steps in Procedures A4 to D4.

[0103] Procedure B7. Set a 5 μm x 5 μm rectangular measurement field in the binarized image. Use the image analysis software described above to measure the number of first particles in the measurement field. If a first particle exists both inside and outside the measurement field, that first particle is considered to be a first particle that exists within the measurement field and is counted.

[0104] Procedure C7. The measurement in Procedure B7 is performed in six different, non-overlapping measurement fields set at the same location as in Procedure C5. In this disclosure, the unit area (25 μm) of the first particle in the six measurement fields is defined as follows: ２ The average number per unit area (25 μm) of the first particle in the metal component is ２ Number per 25 μm ２ This falls under the category of ).

[0105] <Region of First Particle Existence> In the metal member of Embodiment 1, the titanium is composed of a plurality of titanium particles, and at least one of the first particles may exist at the grain boundary of the titanium particles. This further improves the strength of the metal member.

[0106] In this disclosure, the grain boundaries of titanium particles include the first grain boundaries between α-titanium particles made of alpha-titanium, the second grain boundaries between ω-titanium particles made of omega-titanium, and the third grain boundaries between α-titanium particles and ω-titanium particles. In this disclosure, "at least one of the first particles may be present in a grain boundary of titanium particles" means that at least one of the first particles may be present in at least one grain boundary selected from the group consisting of the first grain boundary, the second grain boundary, and the third grain boundary.

[0107] In this disclosure, it is confirmed that titanium is composed of multiple titanium particles, and that the first particle is located at the grain boundary of the titanium particles, by the following procedure.

[0108] Procedure A8. Obtain a backscattered electron image of the metal component according to the procedures in Procedures A4 and B4. Identify the grain boundaries of titanium particles in the backscattered electron image.

[0109] Step B8. Identify the first particle in the binarized image following the steps in Steps A4 to D4.

[0110] Step C8. The backscattered electron image from Step A8, in which the grain boundaries of the titanium particles are identified, is superimposed with the binarized image from Step B8, in which the first particle is identified. If the first particle is located in a place where the grain boundaries of the titanium particles overlap, it is determined that the titanium is composed of multiple titanium particles and that the first particle is located at the grain boundary of the titanium particles. A rectangular measurement field of view of 5 μm × 5 μm is set in the superimposed image. In this disclosure, if at least one first particle present in the measurement field of view is located at the grain boundary of the titanium particles, it is confirmed that at least one of the first particles is located at the grain boundary of the titanium particles.

[0111] In the metal member of Embodiment 1, at least one of the first particles may be located at the grain boundary of the titanium particles, and at least one other may be located within the titanium particles. In the metal member of Embodiment 1, all of the first particles may be located at the grain boundary of the titanium particles.

[0112] <Tensile strength σB and elongation at break δ of the metal member> The tensile strength σB of the metal member in Embodiment 1 may be 400 MPa or more and less than 1550 MPa, 500 MPa or more and 1100 MPa or less, 900 MPa or more and 1100 MPa or less, or 950 MPa or more and 1000 MPa or less.

[0113] The fracture elongation δ of the metal member in Embodiment 1 may be 20% or more and 50% or less, 25% or more and 45% or less, or 30% or more and 45% or less.

[0114] In this disclosure, the tensile strength σB and fracture elongation δ of the metal members are measured in accordance with JIS Z 2241:2011 "Tensile Test Method for Metallic Materials". The test temperature is 23°C ± 5°C.

[0115] <Relationship between tensile strength σBMPa and fracture elongation δ%> In the metal member of Embodiment 1, the tensile strength σBMPa and fracture elongation δ% of the metal member may be related by the following formula I: σB ≥ 1600 - 30δ Formula I In the above formula I, σB ≥ 400 and δ ≥ 20.

[0116] Metal components that satisfy the relationship in equation I above have high strength and high ductility. Conventional metal components such as alpha pure titanium have high elongation at break (hereinafter also referred to as ductility), but their tensile strength (also referred to as strength) is low and they do not satisfy the relationship in equation I above.

[0117] The tensile strength σBMPa and elongation at break δ% of a metal member may be expressed by the following equations I-A or I-B: σB > 1875 - 30δ (Equation I-A) σB > 1900 - 30δ (Equation I-B) In the above equations I-A and I-B, σB ≥ 400 and δ ≥ 20. A metal member satisfying the above relationship of equation I-A or I-B can have even higher strength and higher ductility.

[0118] <Vickers hardness> The Vickers hardness of the metal member in the second region of Embodiment 1 may be 130 Hv or more and 400 Hv or less, 200 Hv or more and 400 Hv or less, or 230 Hv or more and 400 Hv or less. According to this, the metal member has excellent hardness and improved wear resistance.

[0119] In this disclosure, the Vickers hardness of a metal component is measured using the following procedure: The metal material is cut to expose the cross-section. A second region is identified in the cross-section. The Vickers hardness is measured in the second region in accordance with JIS Z 2244:2009 "Vickers hardness test - Test method". The test temperature is 23°C ± 5°C.

[0120] <Heat Resistance Temperature> The heat resistance temperature of the metal member in Embodiment 1 may be 100°C or more and 190°C or less, 120°C or more and 190°C or less, or 140°C or more and 190°C or less. According to this, the metal member can maintain excellent strength even at high temperatures of 100°C or higher.

[0121] The heat resistance temperature of a metal component is measured by comparing the X-ray diffraction pattern at 25°C with the X-ray diffraction pattern at a predetermined temperature using X-ray diffraction analysis. The specific measurement method is as follows:

[0122] Prepare the sample for measurement by polishing the surface of a metal component. Using an X-ray diffractometer, irradiate the sample with X-rays under the following measurement conditions to obtain an X-ray diffraction pattern. The measurement temperature will be selected from a range of temperatures, including 25°C and temperatures exceeding 25°C, and obtain an X-ray diffraction pattern at each temperature.

[0123] <<X-ray diffraction measurement conditions>> Characteristic X-ray: Cu-Kα (wavelength 1.54 Å) Filter: Multilayer mirror optical system: Concentration method X-ray diffraction method: θ-2θ method

[0124] The X-ray diffraction pattern at 25°C is compared with the X-ray diffraction pattern at a predetermined temperature above 25°C (hereinafter also referred to as "predetermined temperature"). If the shapes of both X-ray diffraction patterns match, the sample is judged to have maintained its crystalline structure at the predetermined temperature and to possess heat resistance. Matching shapes of the X-ray diffraction patterns means that the relative positions of all diffraction peaks in the compared X-ray diffraction patterns match, and that the order of the intensities of each diffraction peak also matches.

[0125] The above X-ray diffraction measurement is performed by increasing the temperature until the X-ray diffraction pattern at a predetermined temperature above 25°C has a different shape from the X-ray diffraction pattern at 25°C. From the obtained multiple X-ray diffraction patterns, the X-ray diffraction pattern at the highest temperature that matches the X-ray diffraction pattern at 25°C is identified. The highest temperature is set as the heat resistance temperature of the sample for measurement.

[0126] <Volume of the metal component> The volume of the metal component in Embodiment 1 is 0.001 mm³. ３The above is also acceptable. According to this, because it has sufficient size, it can be easily used for various applications such as implant members, artificial skull fixation members, spinal device fixation members, components of implantable devices, or components of sensor housings. In addition, because a sufficient amount of the second region can be secured, the metal member can have better strength and ductility.

[0127] The volume of the metal component is 0.001 mm³. ３ 100,000 mm ３ The following is also acceptable: 10 mm ３ 100,000 mm ３ The following is also acceptable, or 100 mm ３ 100,000 mm ３ The following is also acceptable: The volume of the metal component is measured by the Archimedes method.

[0128] <Shape of Metal Member> The shape of the metal member in Embodiment 1 is not particularly limited and can be set as appropriate depending on the application. The shape of the metal member may be, for example, a rectangular prism, cylinder, tube, rectangular tube, or flat plate, and may also be a screw shape, nut shape, bolt shape, or washer shape. Furthermore, the shape of the metal member may be a shape suitable for an implant member or a shape suitable for a biomedical metal member. Grooves or the like suitable for the application may be formed on the surface of the metal member. The thickness of the thinnest part of the metal member may be 0.2 mm or more.

[0129] <0.2% yield strength in tensile test> The 0.2% yield strength in the tensile test of the metal member of Embodiment 1 may be 250 MPa or more and 2000 MPa or less, 300 MPa or more and 1000 MPa or less, 600 MPa or more and 900 MPa or less, or 730 MPa or more and 870 MPa or less.

[0130] The 0.2% proof stress in tensile tests of metal components shall be measured in accordance with JIS Z 2241:2011 "Tensile Testing Method for Metallic Materials". The test temperature shall be 23°C ± 5°C.

[0131] <0.2% proof stress in compression test> The 0.2% proof stress in the compression test of the metal member of Embodiment 1 may be 580 MPa or more and 5000 MPa or less, 900 MPa or more and 3000 MPa or less, 900 MPa or more and 2000 MPa or less, or 1100 MPa or more and 1500 MPa or less.

[0132] The 0.2% proof stress in compression tests of metal components shall be measured in accordance with JIS R 1608:2003 "Test Method for Compressive Strength of Fine Ceramics". The test temperature shall be 23°C ± 5°C.

[0133] <Method for manufacturing metal components> The method for manufacturing metal components according to Embodiment 1 may include a raw material preparation step, a high-pressure high-temperature treatment step, and a discharge treatment step.

[0134] <<Raw Material Preparation Process>> In the raw material preparation process, a conventional titanium alloy or pure titanium containing 98.8% by mass or more of titanium is prepared as the raw material. The titanium in the titanium alloy and pure titanium is alpha titanium, which has an alpha phase crystal structure.

[0135] ≪High-Pressure, High-Temperature Processing Process≫ The above raw materials are placed in a sample container made of hexagonal boron nitride polycrystalline material, and pressurized to 5 GPa at room temperature using an ultra-high pressure, high-temperature generator, and then heated to 300°C. After that, the pressure is further increased to 10 GPa to 12 GPa, and then heated to 700°C to 900°C and held for 25 to 40 minutes to obtain titanium material. The obtained titanium material has a uniform structure, and the omega titanium content is almost the same from the inside to the surface.

[0136] The ultra-high pressure and high temperature generating device will be explained using Figure 2. As shown in Figure 2, the high-pressure cell 10 of the ultra-high pressure and high temperature generating device comprises a pressure medium 1 having the shape of a regular octahedron, a sample container 2 placed inside the pressure medium 1, and a heating element 3 placed around the sample container 2. The sample container 2 is made of hexagonal boron nitride. The heating element 3 is made of graphite. The raw material 4 is sealed inside the sample container 2. The maximum load of the ultra-high pressure and high temperature generating device is, for example, 2800 tons.

[0137] ≪Discharge Treatment Process≫ In the discharge treatment process, a discharge treatment is performed on the titanium material to obtain a metal component. Specifically, in argon gas or pure water, an electric current is passed through the surface of the titanium material with a wire electrode or a planar electrode close to it to generate a discharge, thereby discharging the surface of the titanium material. In the region of the titanium material where the discharge treatment has been performed, a reverse phase transition from omega titanium to alpha titanium occurs, and the alpha titanium content increases. As a result, a first region is formed in the area within 3 μm of the surface of the titanium material, in which the alpha titanium content is 10 volume percent or more, and the metal component of Embodiment 1 is obtained.

[0138] The discharge treatment conditions can be a discharge voltage of 0.05 to 5 kV, a discharge current of 0.01 to 500 A, and a pulse width of 1 to 1000 μs.

[0139] By adjusting the size of the area where the discharge treatment is performed on the surface of the titanium material, the percentage of the area of ​​the first region relative to the total surface area of ​​the metal component can be adjusted.

[0140] [Embodiment 2: Implant Member] The implant member of one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 2") is an implant member made of the metal member of Embodiment 1. The implant member of Embodiment 2 has a higher omega titanium content than conventional implant members made of titanium material mainly composed of alpha titanium, and can have excellent strength and ductility. Furthermore, because the implant member of Embodiment 2 contains alpha titanium on its surface, it is easy to surface treat and has excellent biocompatibility.

[0141] Figure 3 is a schematic diagram showing the basic structure of an implant 30 using the implant member of Embodiment 2. The implant 30 may include an implant body 31 embedded in the tooth root, an artificial tooth 34 fixed to the tip of the implant body, and an abutment 32 and an artificial tooth fixing screw 33 connecting the implant body 31 and the artificial tooth 34. The implant member of Embodiment 2 may be the implant body, an abutment, or an artificial tooth fixing screw.

[0142] The implant in Figure 3 is a two-piece type in which the implant body and the abutment are separate components. The implant component in Embodiment 2 may be a one-piece type implant component in which the implant body and the abutment are integrated.

[0143] In the implant member of Embodiment 2, the first region of the metal member can constitute the surface of the implant member that comes into contact with the living body, or a surface that has the potential to come into contact with the living body. This further improves safety for the living body.

[0144] [Embodiment 3: Biomedical Metal Member] The biomedical metal member of one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 3") consists of the metal member of Embodiment 1. The biomedical metal member of Embodiment 3 has a higher omega titanium content than conventional biomedical metal members made of titanium material mainly composed of alpha titanium, and can have excellent strength and ductility. Furthermore, because the biomedical metal member of Embodiment 3 contains alpha titanium on its surface, it is easy to surface treat and has excellent safety for living organisms.

[0145] The biocompatible metal member in Embodiment 3 may be, for example, a member for fixing an artificial skull, a member for fixing a spinal device, a component of an implantable device, or a component of a sensor housing. The member for fixing an artificial skull or a member for fixing a spinal device may be a rod, a plate, or a screw.

[0146] In the bio-metal member of Embodiment 3, the first region of the metal member can constitute a surface of the bio-metal member that comes into contact with a living organism, or a surface that has the potential to come into contact with a living organism.

[0147] This embodiment will be described in more detail by reference to examples. However, this embodiment is not limited by these examples.

[0148] [Preparation of Titanium Materials] <Sample 1 to Sample 6> For each sample, alpha-pure titanium having the composition described in the "Raw Material Composition" column of Table 1 was prepared as the raw material. The titanium contained in the raw material of each sample is alpha-titanium.

[0149]

[0150] The raw materials for each sample were placed in a sample container made of hexagonal boron nitride polycrystalline material. Using a multi-anvil ultra-high pressure and high temperature generator (Voggenreiter's "mavo press LPR 1000-400 / 50", with a graphite heating element and a maximum load of 2800 tons), the samples were pressurized to 5 GPa at room temperature and then heated to 300°C. Subsequently, the samples were further pressurized to the pressure indicated in the "Pressure" column of Table 1, heated to the temperature indicated in the "Temperature" column of Table 1, and held for the time indicated in the "Holding Time" column of Table 1 to obtain the titanium material. The obtained titanium material had dimensions of 10 mm in height and a volume of 500 mm³. ３ It was cylindrical in shape.

[0151] [Preparation of Alpha Pure Titanium] <Samples 101 to 106> For samples 101 to 106, alpha pure titanium, which is the raw material for samples 1 to 6, was prepared. Sample 102 corresponds to JIS-1, sample 103 corresponds to JIS-2, sample 104 corresponds to JIS-3, and samples 105 and 107 correspond to JIS-4. Samples 101 and 106 were prepared for this embodiment. In sample 101, the total amount of raw materials is 100.0001% by mass, which is due to rounding. Hereinafter, alpha pure titanium in samples 101 to 106 will also be referred to as titanium material.

[0152] [Measurement of Titanium Materials] For each sample of titanium material, the following measurements were taken: titanium (Ti) content, percentage of omega titanium by mass (shown in the "ω-Ti / Ti" column in Table 2), content c of components other than titanium, type of impurity element, total content of titanium and impurity elements (Ti + total content of impurity elements), content of the first particle, average particle size of the first particle, number of first particles per unit area, presence or absence of titanium particles at grain boundaries of the first particle (shown in the "Presence of First Particles at Grain Boundaries" column in Table 3), tensile strength σB, elongation at break δ, average particle size of titanium particles, D90 / D10 of titanium particles, Vickers hardness, heat resistance temperature (samples 1 to 6 only), volume, 0.2% yield strength in tensile tests, and 0.2% yield strength in compression tests. Each measurement item was performed in accordance with the measurement method for each measurement item of the metal member described in Embodiment 1. The results are shown in Tables 2 to 5.

[0153] In the "Presence of the first particle at the grain boundary" column of Table 3, "Yes" indicates that the first particle is present at the grain boundary of the titanium particle, and "No" indicates that the first particle is not present at the grain boundary of the titanium particle.

[0154] For each sample's metal component, it was confirmed whether the following relationship I was satisfied: σB ≥ 1600 - 30δ Equation I In the above equation I, σB ≥ 400 and δ ≥ 20.

[0155] In the "Equation I" column of Table 4, "Yes" indicates that the relationship of Equation I is satisfied, and "No" indicates that the relationship of Equation I is not satisfied.

[0156]

[0157]

[0158]

[0159]

[0160] From the results above, it was confirmed that the strength of each titanium material from Sample 1 to Sample 6 was higher than that of the titanium material with the same titanium content and in which the titanium is alpha titanium, indicating that the titanium materials from Sample 1 to Sample 6 possess high strength.

[0161] [Fabrication of Metal Components] Multiple samples of titanium material were prepared for each of Sample 1 to Sample 6. Discharge treatment was performed on the entire surface of each titanium material to obtain metal components for Samples 11 to 16, Samples 21 to 26, and Samples 31 to 36. In the discharge treatment, an electric current was passed through the surface of the titanium material in an argon gas environment, with a wire electrode close to the surface, generating a discharge and treating the entire surface of the titanium material. The discharge treatment conditions for each sample are shown in Table 6.

[0162]

[0163] [Measurement of Metal Components] For each sample of metal component, the titanium content, the content of components other than titanium, the types of components other than titanium, the titanium crystal structure, the presence or absence of the first region, the alpha titanium content of the first region, the standard deviation of the alpha titanium content in the first region, and the omega titanium content of the second region were measured. The specific measurement method is as described in Embodiment 1. The results are shown in Table 7. It was confirmed that the first region was present in all samples.

[0164]

[0165] The metal components of Samples 11 to 16, Samples 21 to 26, and Samples 31 to 36 correspond to the examples.

[0166] For each sample of metal component, the content of the first particles, the average particle size of the first particles, the number of first particles per unit area, the presence or absence of titanium particles at the grain boundaries of the first particles, tensile strength σB, elongation at break δ, average particle size and D90 / D10 of the crystal grains constituting the second region, Vickers hardness, heat resistance temperature (samples 1 to 6 only), volume, 0.2% yield strength in tensile tests, and 0.2% yield strength in compression tests were measured. It was confirmed that all samples were almost identical to the values ​​of the titanium material before discharge treatment. Furthermore, it was confirmed that the average particle size and D90 / D10 of the crystal grains constituting the second region were almost identical to the average particle size and D90 / D10 of titanium particles in the titanium material.

[0167] Figure 4 is a backscattered electron image of the metal component of sample 35. In the backscattered electron image of Figure 4, the areas shown in black are the first particles 25, and the areas shown in gray to white are titanium particles. From this backscattered electron image, it can be confirmed that the first particles 25 are located at the grain boundaries of the titanium particles. Figure 5 is a backscattered electron image of the titanium material made of alpha-pure titanium of sample 105. In the backscattered electron image of Figure 5, it can be confirmed that the first particles are not present.

[0168] While embodiments and examples of this disclosure have been described above, it is intended from the outset that the configurations of each of the embodiments and examples described above may be combined or modified in various ways as appropriate. The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments and examples described above, and all modifications within the meaning and scope of the claims are intended to be included.

[0169] 1 Pressure medium, 2 Sample container, 3 Heating element, 4 Raw material, 10 High-pressure cell, 20 Metal component, 21 First region, 22 Second region, 23 Surface, 24 Other regions, 25 First particle, 30 Implant, 31 Implant body, 32 Abutment, 33 Screw for fixing artificial tooth, 34 Artificial tooth.

Claims

1. A metal member containing 98.8% by mass or more of titanium, wherein the metal member comprises a first region and a second region, the first region being within 3 μm of the surface of the metal member and having an alpha-phase crystal structure with a content of 10% by volume or more of alpha titanium, the second region being 40 μm or more of the surface of the metal member, the content of omega-titanium having an omega-phase crystal structure in the second region being 95% by volume or more, the metal member containing 0.1% by volume or more and 2.0% by volume or less of first particles, and in a spectrum obtained by elemental analysis of the first particles using an energy-dispersive X-ray spectrometer attached to a scanning electron microscope, the ratio C2 / C1 of the maximum peak intensity C2 derived from carbon to the maximum peak intensity C1 derived from titanium is 0.5 or more.

2. The metal member according to claim 1, wherein the titanium comprises a plurality of titanium particles, and at least one of the first particles is present at the grain boundary of the titanium particles.

3. The metal member according to claim 1 or claim 2, wherein in at least a portion of the first region, the alpha titanium content is 10% by volume or more and less than 50% by volume.

4. The metal member according to claim 1 or claim 2, wherein in at least a portion of the first region, the alpha titanium content is 50% by volume or more and 100% by volume or less.

5. The metal member according to any one of claims 1 to 4, wherein in at least a portion of the first region, the standard deviation of the alpha titanium content is 1.5 volume percent or more.

6. The metal member according to any one of claims 1 to 5, wherein the average particle size of the first particle is 5 nm or more and 100 nm or less.

7. In the first image obtained by binarizing the backscattered electron image obtained by observing the cross-section of the metal member at 10,000x magnification using the scanning electron microscope, the number of the first particles per unit area is 10 particles / 25 μm. ２ More than 100 pieces / 25μm ２ The metal member according to any one of claims 1 to 6, which is as follows:

8. An implant member comprising a metal member according to any one of claims 1 to 7.

9. A biocompatible metal member comprising the metal member described in any one of claims 1 to 7.

10. The bio-metal member according to claim 9, wherein the bio-metal member is a member for fixing an artificial skull, a member for fixing a spinal device, a component of an implantable device, or a component of a sensor housing.

11. The biomedical metal member according to claim 10, wherein the artificial skull fixing member or the spinal device fixing member is a rod, a plate, or a screw.

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