Medical alpha + beta two-phase Ti15Mo titanium alloy sheet and preparation method thereof

Abstract

The invention belongs to the technical field of nonferrous metal material processing, and relates to a medical alpha + beta two-phase Ti15Mo titanium alloy sheet and a preparation method thereof. The preparation method specifically comprises the following steps: firstly, preparing an alpha + beta two-phase Ti15Mo alloy plate blank with uniform transverse and longitudinal tissues through hot rolling; then, through solution treatment, the plate blank is placed in a heat treatment furnace to be heated and subjected to heat preservation, and solution treatment and cooling treatment with strict process control are conducted; and finally, carrying out aging treatment and surface treatment to prepare the alpha + beta two-phase Ti15Mo alloy sheet with the required size. The Ti15Mo alloy sheet prepared by the method has the advantages of numerous specifications, uniform tissue, good model, good corrosion resistance, high biocompatibility with human tissue as a medical titanium alloy and the like, and the finished product has stable performance, meets the product verification of large-scale medical manufacturers, and is beneficial to promoting the upgrading of domestic medical products.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal material processing technology, and relates to Ti15Mo titanium alloy, and more particularly to a medical α+β two-phase Ti15Mo titanium alloy thin plate and its preparation method. Background Technology

[0002] Ti15Mo (UNS R58150) titanium alloy is a metastable β-type titanium alloy with high specific strength, excellent fatigue resistance, outstanding corrosion resistance, and good biocompatibility, and is considered a representative material of the third generation of novel medical titanium alloys. As an ideal replacement for the widely used Ti-6Al-4V alloy, this alloy is often processed into thin plates of various specifications and widely used in surgical implants in trauma orthopedics, spinal surgery, and other fields. Compared with Ti-6Al-4V, the α+β dual-phase Ti15Mo alloy exhibits superior fatigue performance and biocompatibility, showing significant potential for clinical applications.

[0003] However, in industrial production, α+β duplex Ti15Mo titanium alloys are extremely sensitive to hot working temperatures. With the increasing variety of product specifications and dimensional complexity, precisely controlling the temperature range of the sheet metal during rolling and heat treatment becomes extremely difficult, making the uniformity of its microstructure and consistency of its properties a key challenge in engineering applications. Furthermore, because metastable β-type titanium alloy sheets require special processes for controlling the duplex microstructure, flatness control is also a major technical challenge, making the actual processing difficulty far greater than that of Ti-6Al-4V sheets.

[0004] Currently, there is almost no large-scale application of Ti15Mo alloy raw material plates in the domestic medical market, mainly due to the lack of mature engineering preparation technology. Therefore, developing a process for mass-producing Ti15Mo titanium alloy thin plates with uniform α+β dual-phase microstructure is of great strategic significance for filling this gap in the domestic market. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a medical α+β two-phase Ti15Mo titanium alloy thin plate and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: On one hand, this invention provides a method for preparing a medical α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1, Billet preparation: Prepare Ti15Mo alloy slabs with uniform cross and longitudinal microstructure by hot rolling; Step 2, Solution treatment: The Ti15Mo alloy slab is placed in a heat treatment furnace and heated and held at that temperature, and then air-cooled. The heating temperature is 30°C to 70°C below the phase transformation point of the Ti15Mo alloy, and the holding time is 60 min to 120 min. Step 3, Aging Treatment: The Ti15Mo alloy slab after the solution treatment in Step 2 is placed in a heat treatment furnace and heated and held at that temperature for AC aging treatment. Step 4, Surface treatment: The surface of the Ti15Mo alloy slab after the aging treatment in Step 3 is treated to complete the preparation of the α+β two-phase Ti15Mo titanium alloy thin plate of the target specifications.

[0007] Specifically, in step 3, the heating temperature is 100℃~210℃ below the phase transformation point of Ti15Mo alloy, and the holding time is 6h~8h.

[0008] Furthermore, in step 3, a steel plate is placed on top of the Ti15Mo alloy slab after solution treatment, and the area of ​​the steel plate is greater than or equal to the area of ​​the Ti15Mo alloy slab.

[0009] Specifically, the thickness of the steel plate is 50mm to 100mm.

[0010] Specifically, when the Ti15Mo alloy plate is subjected to solution treatment and aging treatment, there should be a time interval of more than 30 seconds between the plate being removed from the furnace. When the furnace temperature drops to 10°C below the set temperature, the furnace should be shut down for heat preservation.

[0011] Further, step 1 specifically includes: Step 1.1: Roll the thick plate with uniform and fine α+β microstructure into a blank until the thickness is 40mm~50mm, at a blanking temperature of T. β +30℃~60℃; Step 1.2, then in T β The intermediate slab is rolled in two passes at a temperature of -40℃ to 70℃ to obtain a thickness of 4mm to 10mm. Step 1.3: Based on the intermediate slab, control the deformation amount per pass to 10%~20% to obtain a Ti15Mo alloy slab with uniform and fine cross-sectional and longitudinal microstructure.

[0012] Furthermore, in the Ti15Mo titanium alloy sheet, the mass percentage of each alloy component is as follows: Mo 14.00wt.%~16.00wt.%, O ≤0.2wt.% and the balance is Ti element and other unavoidable impurities.

[0013] On the other hand, the present invention also provides a medical α+β two-phase Ti15Mo titanium alloy sheet prepared by the preparation method described in part or all of the above, with the following warm tensile properties: tensile strength R m ≥1032MPa, yield strength R p0.2 ≥959MPa, elongation at break (A / %) ≥12.5.

[0014] Specifically, the thickness of the Ti15Mo titanium alloy sheet is 4mm to 8.5mm.

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1) This invention uses rolled slabs to undergo heat treatment in a heat treatment furnace for heat treatment, including heat treatment, heat treatment, aging, and surface polishing. The final product has various properties (strength, elongation after fracture) that meet the standards, are superior to and replace traditional TC4 products. Moreover, this product has passed the acceptance and preliminary clinical application verification of large domestic medical manufacturers, meets the enterprise standards of large domestic medical manufacturers, and has good market application prospects. 2) This invention enables the mass production of Ti15Mo sheet products in engineering, filling a gap in the domestic engineering technology field; after rolling, the finished products are available in a variety of specifications, which can meet the needs of most medical manufacturers; the parameters of the solution aging treatment process are strictly controlled, and the titanium alloy sheet has high stability of microstructure and properties; through mature rolling technology, the sheet shape is well controlled after rolling, which reduces the difficulty and cost of downstream processing, making it suitable for promotion in the engineering field. Attached Figure Description

[0016] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the preparation method of the medical α+β two-phase Ti15Mo titanium alloy thin plate provided by the present invention; Figure 2(a) shows the microstructure of the Ti15Mo alloy slab before solution treatment, and Figure 2(b) shows the microstructure of the Ti15Mo alloy slab after solution treatment. Figure 3(a) is a microscopic image of the transverse structure of the intermediate slab before rolling in step 1.3; Figure 3(b) is a microscopic image of the transverse structure of the intermediate slab after rolling in step 1.3; Figure 3(c) is a microscopic image of the longitudinal structure of the intermediate slab before rolling in step 1.3; and Figure 3(d) is a microscopic image of the longitudinal structure of the intermediate slab after rolling in step 1.3. Figure 4(a) is a high-magnification microstructure of the transverse structure of the solution-treated and aged Ti15Mo titanium alloy sheet obtained in Example 1 of the present invention; Figure 4(b) is a high-magnification microstructure of the longitudinal structure of the solution-treated and aged Ti15Mo titanium alloy sheet obtained in Example 1 of the present invention. Figure 5 The image shows a high-magnification microstructure of a solution-treated and aged Ti15Mo titanium alloy sheet prepared as a comparative example. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0020] See Figure 1 This invention provides a method for preparing a medical α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1, Billet Preparation: A Ti15Mo alloy slab with uniform transverse and longitudinal microstructure is prepared by hot rolling; specifically, Step 1 involves: Step 1.1: Roll the thick plate with uniform and fine α+β microstructure into a blank until the thickness is 40mm~50mm, at a blanking temperature of T. β +30℃~60℃; Step 1.2, then in T β The intermediate slab is rolled in two passes at a temperature of -40℃ to 70℃ to obtain a thickness of 4mm to 10mm. Step 1.3: Based on the intermediate slab, control the deformation amount per pass to 10%~20% to obtain a Ti15Mo alloy slab with uniform and fine cross-sectional and longitudinal microstructure, see Figures 3(a) to 3(d); Step 2, Solution treatment: The Ti15Mo alloy slab is placed in a heat treatment furnace and heated and held at that temperature, and then air-cooled. The heating temperature is 30°C to 70°C below the phase transformation point of the Ti15Mo alloy, and the holding time is 60 min to 120 min. Step 3, Aging Treatment: The Ti15Mo alloy slab after solution treatment in Step 2 is placed in a heat treatment furnace and heated and held at the same temperature for AC aging treatment; in Step 3, the heating temperature is 100℃~210℃ below the phase transformation point of Ti15Mo alloy, and the holding time is 6h~8h. Step 4, Surface treatment: The surface of the Ti15Mo alloy slab after the aging treatment in Step 3 is treated to complete the preparation of the α+β two-phase Ti15Mo titanium alloy thin plate of the target specifications.

[0021] In step 2, as shown in Figures 2(a) and 2(b), by performing a solution treatment at 30°C to 70°C below the phase transformation point of the Ti15Mo alloy, the content of the primary α phase in the microstructure of the plate can be controlled between 20% and 40%, and the α phase is made equiaxed, eliminating the anisotropy caused by the rolling of the plate, resulting in better mechanical properties compared to the processed state.

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Example 1 See Figure 1 As shown in the figure, this embodiment provides a method for preparing a medical α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1: Preparation of billet, the phase transformation point of which is 770℃; A 100mm thick slab with a uniform and fine α+β microstructure is rolled to a thickness of 50mm at a rolling temperature of T. β +30℃ (i.e., 800℃), then at T β The alloy slab is rolled twice at a temperature of -40℃ (i.e. 730℃) and then rolled to a thickness of δ=9.0mm. Step 2, Solution treatment The slab that has undergone step 1 is heated and held at a temperature of T in a Class III heat treatment furnace. β -70℃ (i.e. 700℃), heat preservation time is 1 hour, and air cooling treatment is carried out. In order to ensure the performance and uniformity of the board, the board must be placed in the effective heating zone. The loading and placement of the board must be strictly controlled. The board must be laid flat on the rollers and stacking is not allowed.

[0024] Step 3, Time-sensitive processing The slab after solution treatment in step 2 is placed in a Class III heat treatment furnace and heated to T. β -150℃ (i.e. 620℃), heat preservation for 6 hours, AC aging treatment. To prevent deformation of the plate during the heat treatment process, a 316L stainless steel plate with a thickness of 50mm and an area not less than that of the slab blank is pressed on the slab blank. All slab blanks must be placed in the effective heating zone. Step 4: Finished product surface treatment After the aging treatment in step 3, the slab is subjected to surface oxide scale treatment on a bridge multi-head mill and finally processed to obtain a Ti15Mo titanium alloy thin plate with a thickness of δ=8.1mm. The dimensional tolerance must meet +0.5 / 0.

[0025] To further verify the effectiveness of the technical solution provided by this invention, the solution-treated and aged Ti15Mo titanium alloy sheet obtained in Example 1 was analyzed using scanning electron microscopy, and its high-magnification microstructure is shown in Figure 4. The yield strength and tensile strength of the finished sheet were tested using a quasi-static tensile testing device, and the elongation was tested using an electronic extensometer. The results are shown in Table 1.

[0026] Table 1. Room temperature tensile properties of the Ti15Mo titanium alloy sheet obtained in Example 1 As shown in Figures 4(a) and 4(b), the high-magnification microstructure of the solution-treated and aged Ti15Mo alloy sheet consists of equiaxed primary α phase and lamellar secondary α phase precipitated on a β matrix. The test results in Table 2 above show that the solution-treated and aged Ti15Mo titanium alloy sheet obtained in this invention exhibits stable finished product performance and meets the α+β annealing + aging standard requirements of AMS F2066 "Standard Specification for Deformed Ti15Mo Alloys for Surgical Implants".

[0027] Example 2 This embodiment provides a method for preparing a medical-grade α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1: Preparation of billet, the phase transformation point of which is 770℃; A 100mm thick slab with a uniform and fine α+β microstructure is rolled to a thickness of 50mm at a rolling temperature of T. β +50℃ (i.e., 820℃), then at T β The alloy slab is rolled in two passes at a temperature of -60℃ (i.e. 710℃), and the deformation per pass is strictly controlled at 10%~20% to achieve a thickness of δ=7.2mm. Step 2, Solution treatment The slab that has undergone step 1 is heated and held at a temperature of T in a Class III heat treatment furnace. β -30℃ (i.e. 740℃), heat preservation time is 1.5h, and air cooling treatment is carried out. In order to ensure the performance and uniformity of the board, the board must be placed in the effective heating zone. The loading and placement of the board must be strictly controlled. The board must be laid flat on the rollers and stacking is not allowed.

[0028] Step 3, Time-sensitive processing The slab after solution treatment in step 2 is placed in a Class III heat treatment furnace and heated to T. β -100℃ (i.e. 670℃), heat preservation for 8 hours, AC aging treatment. To prevent the plate from deforming during the heat treatment process, a 316L stainless steel plate with a thickness of 50mm and an area not less than that of the slab is pressed on top of the slab. All slabs must be placed in the effective heating zone. Step 4: Finished product surface treatment After the aging treatment in step 3, the slab is subjected to surface oxide scale treatment on a bridge multi-head mill and finally processed to obtain a Ti15Mo titanium alloy thin plate with a thickness of δ=6.4mm. The dimensional tolerance must meet +0.4 / 0.

[0029] Example 3 This embodiment provides a method for preparing a medical-grade α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1: Preparation of billet, the phase transformation point of which is 770℃; A 100mm thick slab with a uniform and fine α+β microstructure is rolled to a thickness of 50mm at a rolling temperature of T. β +60℃ (i.e., 830℃), then at T β The alloy slab is rolled twice at a temperature of -70℃ (i.e. 700℃) and then rolled to a thickness of δ=5.2mm. Step 2, Solution treatment The slab that has undergone step 1 is heated and held at a temperature of T in a Class III heat treatment furnace. β -40℃ (i.e. 730℃), heat preservation time is 120min, and air cooling treatment is carried out. In order to ensure the performance and uniformity of the board, the board must be placed in the effective heating zone. The loading and placement of the board must be strictly controlled. The board must be laid flat on the rollers and stacking is not allowed.

[0030] Step 3, Time-sensitive processing The slab after solution treatment in step 2 is placed in a Class III heat treatment furnace and heated to T. β -210℃ (i.e. 560℃), heat preservation for 8 hours, AC aging treatment. To prevent the plate from deforming during the heat treatment process, a 316L stainless steel plate with a thickness of 50mm and an area not less than that of the slab is pressed on top of the slab. All slabs must be placed in the effective heating zone. Step 4: Finished product surface treatment After the aging treatment in step 3, the slab is subjected to surface oxide scale treatment on a bridge multi-head mill and finally processed to obtain a Ti15Mo titanium alloy thin plate with a thickness of δ=4.3mm. The dimensional tolerance must meet +0.3 / 0.

[0031] Comparative Example This comparative example provides a method for preparing a medical-grade α+β two-phase Ti15Mo titanium alloy thin plate, the specific steps of which are as follows: Step 1: Preparation of billet, the phase transformation point of which is 770℃; A 100mm thick slab with a uniform and fine α+β microstructure is rolled to a thickness of 50mm at a rolling temperature of T. β +60℃ (i.e., 830℃), then at T β The alloy slab is rolled twice at a temperature of -70℃ (i.e. 700℃) and then rolled to a thickness of δ=5.2mm. Step 2, Solution treatment The slab that has undergone step 1 is heated and held at a temperature of T in a Class III heat treatment furnace. β -20℃ (i.e. 750℃), heat preservation time is 120min, and air cooling treatment is carried out. In order to ensure the performance and uniformity of the board, the board must be placed in the effective heating zone. The loading and placement of the board must be strictly controlled. The board must be laid flat on the rollers and stacking is not allowed.

[0032] Step 3, Time-sensitive processing The slab after solution treatment in step 2 is placed in a Class III heat treatment furnace and heated to T. β -270℃ (i.e. 500℃), heat preservation for 8 hours, AC aging treatment. To prevent the plate from deforming during the heat treatment process, a 316L stainless steel plate with a thickness of 50mm and an area not less than that of the slab is pressed on top of the slab. All slabs must be placed in the effective heating zone. Step 4: Finished product surface treatment After the aging treatment in step 3, the slab is subjected to surface oxide scale treatment on a bridge multi-head mill and finally processed to obtain a Ti15Mo titanium alloy thin plate with a thickness of δ=4.3mm. The dimensional tolerance must meet +0.3 / 0.

[0033] Combination Figure 5 From an organizational perspective, the content of the primary α phase is low (<10%), and from a performance perspective, the elongation rate will be low, failing to meet the requirements of the application standards.

[0034] The titanium alloy sheets prepared in Examples 1-3 above can achieve effective control of tensile strength in the range of 900-1100MPa and yield strength in the range of 800-1000MPa by adjusting the solution temperature and aging temperature, while the elongation is not less than 10%, so as to meet the different processing and performance requirements of customers as much as possible, and finally match the usage requirements in specific medical implantation scenarios, thereby expanding the cost advantage of this process in engineering.

[0035] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0036] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a medical-grade α+β two-phase Ti15Mo titanium alloy thin plate, characterized in that, The specific steps are as follows: Step 1, Billet preparation: Prepare Ti15Mo alloy slabs with uniform cross and longitudinal microstructure by hot rolling; Step 2, Solution treatment: The Ti15Mo alloy slab is placed in a heat treatment furnace and heated and held at that temperature, and then air-cooled. The heating temperature is 30°C to 70°C below the phase transformation point of the Ti15Mo alloy, and the holding time is 60 min to 120 min. Step 3, Aging Treatment: The Ti15Mo alloy slab after the solution treatment in Step 2 is placed in a heat treatment furnace and heated and held at that temperature for AC aging treatment. Step 4, Surface treatment: The surface of the Ti15Mo alloy slab after the aging treatment in Step 3 is treated to complete the preparation of the α+β two-phase Ti15Mo titanium alloy thin plate of the target specifications.

2. The method for preparing medical α+β two-phase Ti15Mo titanium alloy thin plates according to claim 1, characterized in that, In step 3, the heating temperature is 100℃~210℃ below the phase transformation point of Ti15Mo alloy, and the holding time is 6h~8h.

3. The method for preparing medical α+β two-phase Ti15Mo titanium alloy thin plates according to claim 1, characterized in that, In step 3, a steel plate is placed on top of the Ti15Mo alloy slab after solution treatment, and the area of ​​the steel plate is greater than or equal to the area of ​​the Ti15Mo alloy slab.

4. The method for preparing the medical α+β two-phase Ti15Mo titanium alloy thin plate according to claim 3, characterized in that, The thickness of the steel plate is 50mm to 100mm.

5. The method for preparing medical α+β two-phase Ti15Mo titanium alloy thin plates according to claim 1, characterized in that, When the Ti15Mo alloy plate is subjected to solution treatment and aging treatment, there should be a time interval of more than 30 seconds between the plate being removed from the furnace. When the furnace temperature drops to 10°C below the set temperature, the furnace should be shut down for heat preservation.

6. The method for preparing medical α+β two-phase Ti15Mo titanium alloy thin plates according to claim 1, characterized in that, Step 1 specifically involves: Step 1.1: Roll the thick plate with uniform and fine α+β microstructure into a blank until the thickness is 40mm~50mm, at a blanking temperature of T. β +30℃~60℃; Step 1.2, then in T β The intermediate slab is rolled in two passes at a temperature of -40℃ to 70℃ to obtain a thickness of 4mm to 10mm. Step 1.3: Based on the intermediate slab, control the deformation amount per pass to 10%~20% to obtain a Ti15Mo alloy slab with uniform and fine cross-sectional and longitudinal microstructure.

7. The method for preparing a medical α+β two-phase Ti15Mo titanium alloy thin plate according to any one of claims 1 to 6, characterized in that, The mass percentages of each alloy component in the Ti15Mo titanium alloy sheet are as follows: Mo 14.00wt.%~16.00wt.%, O≤0.2wt. / %, with the balance being Ti and other unavoidable impurities.

8. A medical-grade α+β two-phase Ti15Mo titanium alloy sheet prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The room temperature tensile properties are as follows: tensile strength R m ≥1032MPa, yield strength R p0.2 ≥959MPa, elongation at break (A / %) ≥12.

5.

9. The medical α+β two-phase Ti15Mo titanium alloy sheet according to claim 8, characterized in that, The thickness of the Ti15Mo titanium alloy sheet is 4mm to 8.5mm.

Images