Preparation method of medical titanium alloy with ultrahigh yield strength and low modulus

Abstract

The application discloses a preparation method of a medical titanium alloy with ultrahigh yield strength and low modulus, and the method comprises the following steps: heating, heat preservation and cooling of a TC4-5Cu alloy formed by selective laser melting at 800-850 DEG C, so that alpha+alpha' organization is transformed into alpha+alpha'', and a low-modulus high-strength copper-containing dual-phase titanium alloy is obtained. The original alpha' acicular organization formed by selective laser melting can be transformed into alpha'' lamellar organization and Ti2Cu is precipitated by the preparation method, so that the whole treatment process is simple, and the influencing factors are small; the lamellar alpha'' phase and the precipitated Ti2Cu phase obtained after the preparation method are subjected to heat treatment, and have the properties of ultrahigh yield strength and low Young's modulus, so that the phenomenon of modulus mismatch of the TC4-5Cu alloy in biomedical applications is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of dual-phase titanium alloy technology, specifically relating to a method for preparing a medical titanium alloy with ultra-high yield strength and low modulus. Background Technology

[0002] Titanium and titanium alloys are widely used in the manufacture of artificial joints, dental implants, and other orthopedic implants due to their excellent mechanical properties, biocompatibility, corrosion resistance, and low elastic modulus. Although titanium (~110 MPa) has a low elastic modulus, it is still much higher than that of human bone tissue (~30 MPa). This still cannot prevent the "stress shielding" effect caused by the mismatch between the mechanical properties of the implant and the bone tissue, leading to less new bone formation on the implant surface or bone atrophy around the implant under long-term use. Porous materials, with their porous structure, can adjust the elastic modulus of the implant by changing the size and shape of the pores, allowing it to match the range of natural bone. Implanting bone tissue with similar mechanical properties can minimize the "stress shielding" effect and subsequent bone atrophy. Secondly, infection is one of the most disastrous postoperative complications of orthopedic implants. However, titanium alloys, as implants, do not have antibacterial properties, and implanted titanium carries the risk of infection. In the past, people have mostly focused on the removal of environmental and personal pollution sources and the application of systemic antibiotics during surgery. The new approach is to reduce the risk of infection by functionalizing the surface of the specific mechanism of the source of infection, so that the implant can be used for a longer period of time or permanently in the body. Summary of the Invention

[0003] In view of this, the main objective of the present invention is to provide a method for preparing a medical titanium alloy with ultra-high yield strength and low modulus, which solves the problems of poor yield strength and high Young's modulus of existing duplex titanium alloys.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: a method for preparing a medical titanium alloy with ultra-high yield strength and low modulus, wherein the method is: by heating, holding and cooling the TC4-5Cu alloy clad by selective laser cladding at 800℃~850℃, the α+α' microstructure is transformed into α+α", and a low-modulus, high-yield-strength copper-containing dual-phase titanium alloy is obtained.

[0005] Preferably, the method specifically includes the following steps:

[0006] S1. Prepare bulk TC4-5Cu alloy by selective laser cladding technology using TC4-5Cu mixed powder;

[0007] S2. Gradually raise the temperature to 800℃~850℃ and heat the bulk TC4-5Cu alloy obtained in S1 to obtain the heat-treated bulk TC4-5Cu alloy.

[0008] S3. The heat-treated bulk TC4-5Cu alloy obtained in S2 is placed in an aqueous solution at room temperature for cooling to obtain a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0009] Preferably, in S1, the TC4-5Cu mixed powder comprises, by mass percentage, the following components: 88wt% to 98wt% TC4 and 2wt% to 12wt% Cu.

[0010] Preferably, the TC4 comprises, by mass percentage: 4 wt% to 10 wt% Al, 2 wt% to 6 wt% V, and the remainder being Ti.

[0011] Preferably, the processing parameters of the selective laser cladding technology include laser power, interlayer spacing, layer thickness, and scanning speed.

[0012] Preferably, the laser power is 140W to 170W, the interlayer spacing is 50μm to 100μm, the layer thickness is 20μm to 60μm, and the scanning speed is 1000mm / s to 1400mm / s.

[0013] Preferably, in step S2, the heating rate of the gradual heating is 5-15℃ / min.

[0014] Preferably, in step S2, the heat preservation and heating time is 0.5h to 1.5h.

[0015] Compared with the prior art, 1) the preparation method of the present invention only requires heat treatment to transform the original α' needle-like structure of selective laser melting into α” layered structure and precipitate Ti2Cu, making the whole process simple and with few influencing factors; 2) the layered α” phase and precipitated Ti2Cu phase obtained by the preparation method of the present invention after heat treatment have high yield strength and low Young's modulus, and the yield strength is greater than 1150MPa, thereby effectively improving the phenomenon of modulus mismatch in TC4-5Cu alloy in biomedical applications. Attached Figure Description

[0016] The present invention will now be described in further detail with reference to the accompanying drawings.

[0017] Figure 1 A flowchart illustrating a method for preparing an ultra-high yield strength, low modulus medical titanium alloy according to Embodiment 1 of the present invention;

[0018] Figure 2 The bulk TC4-5Cu alloy and Cu element distribution in the preparation method of an ultra-high yield strength and low modulus medical titanium alloy provided in Embodiment 1 of the present invention;

[0019] Figure 3The microstructure and Cu element distribution of the heat-treated bulk TC4-5Cu alloy after heat treatment in the preparation method of an ultra-high yield strength and low modulus medical titanium alloy provided in Embodiment 1 of the present invention;

[0020] Figure 4 Linear diagrams of the mechanical properties of TC4 and TC4-5Cu alloys in the preparation method of an ultra-high yield strength and low modulus medical titanium alloy provided in Embodiment 1 of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] This invention provides a method for preparing an ultra-high yield strength, low modulus medical titanium alloy, characterized in that the method involves heating, holding, and cooling a TC4-5Cu alloy clad by selective laser cladding at 800℃~850℃ to achieve the transformation of the α+α' microstructure into α+α (effectively transforming the acicular α' microstructure of the titanium alloy into the layered α” phase and precipitating the Ti2Cu phase), thereby obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0023] Furthermore, the method specifically includes the following steps:

[0024] S1. Bulk TC4-5Cu alloy is prepared by selective laser cladding (SLA) using TC4-5Cu mixed powder. The TC4-5Cu mixed powder comprises, by mass percentage, 88wt%–98wt% TC4 and 2wt%–12wt% Cu. The TC4 comprises, by mass percentage, 4wt%–10wt% Al, 2wt%–6wt% V, and the remainder Ti. The processing parameters of the SLA include laser power, interlayer spacing, layer thickness, and scanning speed. The laser power is 140W–170W, the interlayer spacing is 50μm–100μm, the layer thickness is 20μm–60μm, and the scanning speed is 1000mm / s–1400mm / s.

[0025] S2. Gradually increase the temperature to 800℃~850℃ and heat the bulk TC4-5Cu alloy obtained in S1 to obtain the heat-treated bulk TC4-5Cu alloy; the heating rate of the gradual heating is 5-15℃ / min.

[0026] S3. The heat-treated bulk TC4-5Cu alloy obtained in S2 is placed in an aqueous solution at room temperature for cooling to obtain a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0027] The principle of the preparation method of this invention is as follows: First, the phase structure of the TC4-5Cu alloy is adjusted by heat treatment to reduce the elastic modulus of the alloy; second, the precipitation of the Ti2Cu phase by heat treatment endows the TC4-5Cu alloy with excellent antibacterial properties. The advantage of the preparation method of this invention is that by controlling the temperature, time, and cooling method of heat treatment, the transformation of the microstructure is achieved, thereby controlling the material properties. The heat treatment process of this invention is simple and has few influencing factors.

[0028] The following are specific embodiments.

[0029] Example 1

[0030] The ultra-high yield strength and low modulus medical titanium alloy provided in Embodiment 1 of the present invention is achieved through the following steps:

[0031] S1. A bulk TC4-5Cu alloy is prepared by selective laser cladding (SLA) using TC4-5Cu mixed powder. The TC4-5Cu mixed powder comprises 95 wt% TC4 and 5 wt% Cu by mass percentage. The TC4 comprises 6 wt% Al, 4 wt% V, and the remainder Ti by mass percentage. The processing parameters of the SLA include laser power, interlayer spacing, layer thickness, and scanning speed. The laser power is 155 W, the interlayer spacing is 70 μm, the layer thickness is 40 μm, and the scanning speed is 1200 mm / s.

[0032] S2. The crucible is heated to 720°C in a furnace with atmospheric protection at a heating rate of 5-15°C / min. The bulk TC4-5Cu alloy obtained in S1 is then placed into the effective zone of the furnace with atmospheric protection. The temperature inside the furnace is further increased to 820°C at a heating rate of 5-15°C / min and held at that temperature for 1 hour to obtain the heat-treated bulk TC4-5Cu alloy.

[0033] S3. After the heat preservation is completed, the TC4-5Cu alloy is quickly removed and placed in an aqueous solution at room temperature to cool, thereby obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0034] The microstructure of the TC4-5Cu alloy after heat treatment in Example 1 was tested, specifically as follows: Figure 3 As shown, from Figure 3 It can be seen that after heat treatment, the needle-like tissue transforms into a layered tissue.

[0035] The mechanical properties of the TC4-5Cu alloy before and after heat treatment in Example 1 were then tested, specifically as follows: Figure 4 As shown, from Figure 4It can be seen that the yield strength and plasticity of the copper-containing dual-phase titanium alloy material obtained in Example 1 are increased, while the elastic modulus is decreased, and the yield strength is specifically 1186 MPa.

[0036] Example 2

[0037] The medical titanium alloy with ultra-high yield strength and low modulus provided in Embodiment 2 of the present invention is achieved through the following steps:

[0038] S1. A bulk TC4-5Cu alloy is prepared by selective laser cladding (SLA) using TC4-5Cu mixed powder. The TC4-5Cu mixed powder comprises 88 wt% TC4 and 12 wt% Cu by mass percentage. The TC4 comprises 4 wt% Al, 6 wt% V, and the remainder Ti by mass percentage. The processing parameters of the SLA include laser power, interlayer spacing, layer thickness, and scanning speed. The laser power is 140 W, the interlayer spacing is 50 μm, the layer thickness is 20 μm, and the scanning speed is 1000 mm / s.

[0039] S2. The crucible is heated to 720°C in a furnace with a protective atmosphere at a heating rate of 5-15°C / min. The bulk TC4-5Cu alloy obtained in S1 is then placed into the effective zone of the furnace with a protective atmosphere. The temperature inside the furnace is further increased to 800°C at a heating rate of 5-15°C / min and held at that temperature for 0.5 hours to obtain the heat-treated bulk TC4-5Cu alloy.

[0040] S3. After the heat preservation is completed, the TC4-5Cu alloy is quickly removed and placed in an aqueous solution at room temperature to cool, thereby obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0041] The microstructure of the TC4-5Cu alloy after heat treatment in Example 2 was tested. The test results showed that the acicular microstructure was transformed into a layered microstructure after heat treatment.

[0042] The mechanical properties of the TC4-5Cu alloy before and after heat treatment in Example 2 were then tested. The test results showed that the yield strength and plasticity of the copper-containing dual-phase titanium alloy material obtained in Example 2 were increased, while the elastic modulus was decreased. Specifically, the yield strength was 1164 MPa.

[0043] Example 3

[0044] The ultra-high yield strength and low modulus medical titanium alloy provided in Embodiment 3 of the present invention is achieved through the following steps:

[0045] S1. A bulk TC4-5Cu alloy is prepared by selective laser cladding (SLA) using TC4-5Cu mixed powder. The TC4-5Cu mixed powder comprises 98 wt% TC4 and 2 wt% Cu by mass percentage. The TC4 comprises 10 wt% Al, 2 wt% V, and the remainder Ti by mass percentage. The processing parameters of the SLA include laser power, interlayer spacing, layer thickness, and scanning speed. The laser power is 170 W, the interlayer spacing is 100 μm, the layer thickness is 60 μm, and the scanning speed is 1400 mm / s.

[0046] S2. The crucible is heated to 720°C in a furnace with a protective atmosphere at a heating rate of 5-15°C / min. The bulk TC4-5Cu alloy obtained in S1 is then placed into the effective zone of the furnace with a protective atmosphere. The temperature inside the furnace is further increased to 850°C at a heating rate of 5-15°C / min and held at that temperature for 1.5 hours to obtain the heat-treated bulk TC4-5Cu alloy.

[0047] S3. After the heat preservation is completed, the TC4-5Cu alloy is quickly removed and placed in an aqueous solution at room temperature to cool, thereby obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0048] The microstructure of the TC4-5Cu alloy after heat treatment in Example 3 was tested. The test results showed that the acicular microstructure was transformed into a layered microstructure after heat treatment.

[0049] The mechanical properties of the TC4-5Cu alloy before and after heat treatment in Example 3 were then tested. The test results showed that the yield strength and plasticity of the copper-containing dual-phase titanium alloy material obtained in Example 3 were increased, while the elastic modulus was decreased. Specifically, the yield strength was 1172 MPa.

[0050] Example 4

[0051] The medical titanium alloy with ultra-high yield strength and low modulus provided in Embodiment 4 of the present invention is achieved through the following steps:

[0052] S1. A bulk TC4-5Cu alloy is prepared by selective laser cladding (SLA) using TC4-5Cu mixed powder. The TC4-5Cu mixed powder comprises 90 wt% TC4 and 10 wt% Cu by mass percentage. The TC4 comprises 4 wt% Al, 6 wt% V, and the remainder Ti by mass percentage. The processing parameters of the SLA include laser power, interlayer spacing, layer thickness, and scanning speed. The laser power is 160 W, the interlayer spacing is 100 μm, the layer thickness is 20 μm, and the scanning speed is 1200 mm / s.

[0053] S2. The crucible is heated to 720°C in a furnace with a protective atmosphere at a heating rate of 5-15°C / min. The bulk TC4-5Cu alloy obtained in S1 is then placed into the effective zone of the furnace with a protective atmosphere. The temperature inside the furnace is further increased to 820°C at a heating rate of 5-15°C / min and held at that temperature for 1.5 hours to obtain the heat-treated bulk TC4-5Cu alloy.

[0054] S3. After the heat preservation is completed, the TC4-5Cu alloy is quickly removed and placed in an aqueous solution at room temperature to cool, thereby obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy.

[0055] The microstructure of the TC4-5Cu alloy after heat treatment in Example 4 was tested. The test results showed that the acicular microstructure was transformed into a layered microstructure after heat treatment.

[0056] The mechanical properties of the TC4-5Cu alloy before and after heat treatment in Example 4 were then tested. The test results showed that the yield strength and plasticity of the copper-containing dual-phase titanium alloy material obtained in Example 4 were increased, while the elastic modulus was decreased, and the yield strength was specifically 1158 MPa.

[0057] In summary, 1) the preparation method of the present invention only requires heat treatment to transform the original α' needle-like structure formed by selective laser melting into an α” layered structure and precipitate Ti2Cu, making the entire process simple and with few influencing factors; 2) the layered α” phase and precipitated Ti2Cu phase obtained by the preparation method of the present invention after heat treatment have high yield strength and low Young's modulus, and the yield strength is greater than 1150MPa, thereby effectively improving the phenomenon of modulus mismatch in TC4-5Cu alloy in biomedical applications.

[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a medical titanium alloy with ultra-high yield strength and low modulus, characterized in that, The method involves heating, holding, and cooling the TC4-5Cu alloy clad by selective laser cladding at 800℃~850℃ to achieve the transformation of the α+α' microstructure into α+α", thus obtaining a low-modulus, high-strength copper-containing dual-phase titanium alloy. The method specifically includes the following steps: S1. A bulk TC4-5Cu alloy is prepared by selective laser cladding technology using TC4-5Cu mixed powder; the TC4-5Cu mixed powder comprises the following components by mass percentage: 88wt%~98wt% TC4 and 2wt%~12wt% Cu; S2. Gradually increase the temperature to 800℃ and 820℃, and hold the bulk TC4-5Cu alloy obtained in S1 at this temperature to obtain the heat-treated bulk TC4-5Cu alloy; the heating rate of the gradual increase is 5-15℃ / min; the holding time is 0.5h to 1.5h. S3. The heat-treated bulk TC4-5Cu alloy obtained in S2 is placed in an aqueous solution at room temperature for cooling to obtain a low-modulus, high-strength copper-containing dual-phase titanium alloy.

2. The method for preparing an ultra-high yield strength and low modulus medical titanium alloy according to claim 1, characterized in that, The TC4 comprises, by mass percentage, the following components: 4 wt% to 10 wt% Al, 2 wt% to 6 wt% V, and the remainder being Ti.

3. The method for preparing an ultra-high yield strength and low modulus medical titanium alloy according to claim 2, characterized in that, The processing parameters of the selective laser cladding technology include laser power, interlayer spacing, layer thickness, and scanning speed.

4. A method for preparing an ultra-high yield strength, low modulus medical titanium alloy according to any one of claims 1-3, characterized in that, The laser power is 140W~170W, the interlayer spacing is 50 μm~100 μm, the layer thickness is 20 μm~60 μm, and the scanning speed is 1000mm / s~1400mm / s.

Images