Medical β titanium alloy technology design
Compared with the human bone elastic modulus, titanium and titanium alloy are the closest. Currently the most widely used commercially pure titanium and Ti-6Al-4V-based, and the new β alloy, due to have the most similar bone and elastic modulus, the current concern. The process design is:
1, alloy composition
In the design of titanium alloys, α-stable elements (Al, O, N, etc.) and β-stable elements (V, Mo, Nb, etc.) determine the classification of the alloy. Α alloys have only α phase; near α alloys contain a small amount of β stabilizing elements; α + β alloys contain higher β stabilizing elements; and β alloys have only β phases.
It is concluded that Nb. Zr, Mo and Ta are added as medical β titanium alloy. After being added to a definite content, the metastable β phase can be obtained by rapid cooling, which can effectively reduce the elastic modulus of the alloy. However, the addition of such alloying elements the amount cannot be too high, too high will lead to brittle ω phase precipitation, resulting in brittle alloy, elastic modulus increased. Therefore, a reasonable choice and control of the amount added is critical to obtaining the ideal low modulus. www.t0917.com/ Typical is the TNZ series alloys (including Ti-13Nb-13Zr, Ti-13Nb-20Zr, etc.).
2, heat treatment
In order to achieve the ideal β-phase structure, the β-type alloy should be rapidly cooled (such as water quenched) after the β-phase region is sufficiently solution-treated. The heat treatment of the medical β phase alloy is summarized as follows: 1) cold deformation of large deformation amount + hot deformation of annealing or large deformation (β phase region or α + β two phase region); 2) after the thermal mechanical processing, β-phase region of the full solution, fast cooling, as much as possible to get the whole β tissue.
3, grain refinement
Grain refinement is an effective way to obtaining excellent mechanical properties of metallic materials. The superiority of medical implant β-alloy grain after ultra fine grain treatment is that: 1) the strength of the alloy is improved without increasing the elastic modulus, thereby improving the service life; 2) the wear resistance is improved and the implantation The alloy and bone and tissue contact wear and tear; 3) from the material processing and molding point of view, the ultrafine-grained alloy has excellent plastic deformation capacity, and has superplasticity, formability is very good.
The method used in the study is: Ultrafine Grained grains are obtained using the same diameter elbow extrusion method. In addition, there are also two-state microstructures of nano-scale matrix and micro-scale dendrite β phase obtained by the alloying method.
4, surface treatment
In addition to the strength and modulus properties of the alloy, surface wear resistance of medical implant materials has a significant impact on its service life, and poor wear resistance of the implanted alloy will lead to premature wear and failure. The method for improving the wear resistance of implant materials generally adopts surface coating. The traditional coating design mainly considers the biocompatibility, corrosion resistance and surface activity of the alloy, such as Al2O3, TiO2 coating and the like. In recent years, ion implantation, plasma spray coating, surface nitriding, surface carburization and other technologies to improve the surface hardness and wear resistance of the alloy. In particular, a diamond-like carbon coating has a significant impact on improving the wear resistance of the alloy.
In addition, the ultra fine treatment of the near-surface structure of the alloy to obtain submicron or nano-phase grains is also an effective way to improve the wear resistance and fatigue resistance of the material. Such as the use of induction heating quenching treatment, the use of induction heating of the "skin effect" can be realized near the surface of alloy instantaneous induction heating temperature.
In several types of medical implanted titanium alloy, β-type titanium alloy is the latest research, the earlier basic research abroad is more mature, the country is still in the pre-test phase, which requires more researchers to invest more attention and research so that early scientific research Transform into productivity, benefit mankind.
Compared with the human bone elastic modulus, titanium and titanium alloy are the closest. Currently the most widely used commercially pure titanium and Ti-6Al-4V-based, and the new β alloy, due to have the most similar bone and elastic modulus, the current concern. The process design is:
1, alloy composition
In the design of titanium alloys, α-stable elements (Al, O, N, etc.) and β-stable elements (V, Mo, Nb, etc.) determine the classification of the alloy. Α alloys have only α phase; near α alloys contain a small amount of β stabilizing elements; α + β alloys contain higher β stabilizing elements; and β alloys have only β phases.
It is concluded that Nb. Zr, Mo and Ta are added as medical β titanium alloy. After being added to a definite content, the metastable β phase can be obtained by rapid cooling, which can effectively reduce the elastic modulus of the alloy. However, the addition of such alloying elements the amount cannot be too high, too high will lead to brittle ω phase precipitation, resulting in brittle alloy, elastic modulus increased. Therefore, a reasonable choice and control of the amount added is critical to obtaining the ideal low modulus. www.t0917.com/ Typical is the TNZ series alloys (including Ti-13Nb-13Zr, Ti-13Nb-20Zr, etc.).
2, heat treatment
In order to achieve the ideal β-phase structure, the β-type alloy should be rapidly cooled (such as water quenched) after the β-phase region is sufficiently solution-treated. The heat treatment of the medical β phase alloy is summarized as follows: 1) cold deformation of large deformation amount + hot deformation of annealing or large deformation (β phase region or α + β two phase region); 2) after the thermal mechanical processing, β-phase region of the full solution, fast cooling, as much as possible to get the whole β tissue.
3, grain refinement
Grain refinement is an effective way to obtaining excellent mechanical properties of metallic materials. The superiority of medical implant β-alloy grain after ultra fine grain treatment is that: 1) the strength of the alloy is improved without increasing the elastic modulus, thereby improving the service life; 2) the wear resistance is improved and the implantation The alloy and bone and tissue contact wear and tear; 3) from the material processing and molding point of view, the ultrafine-grained alloy has excellent plastic deformation capacity, and has superplasticity, formability is very good.
The method used in the study is: Ultrafine Grained grains are obtained using the same diameter elbow extrusion method. In addition, there are also two-state microstructures of nano-scale matrix and micro-scale dendrite β phase obtained by the alloying method.
4, surface treatment
In addition to the strength and modulus properties of the alloy, surface wear resistance of medical implant materials has a significant impact on its service life, and poor wear resistance of the implanted alloy will lead to premature wear and failure. The method for improving the wear resistance of implant materials generally adopts surface coating. The traditional coating design mainly considers the biocompatibility, corrosion resistance and surface activity of the alloy, such as Al2O3, TiO2 coating and the like. In recent years, ion implantation, plasma spray coating, surface nitriding, surface carburization and other technologies to improve the surface hardness and wear resistance of the alloy. In particular, a diamond-like carbon coating has a significant impact on improving the wear resistance of the alloy.
In addition, the ultra fine treatment of the near-surface structure of the alloy to obtain submicron or nano-phase grains is also an effective way to improve the wear resistance and fatigue resistance of the material. Such as the use of induction heating quenching treatment, the use of induction heating of the "skin effect" can be realized near the surface of alloy instantaneous induction heating temperature.
In several types of medical implanted titanium alloy, β-type titanium alloy is the latest research, the earlier basic research abroad is more mature, the country is still in the pre-test phase, which requires more researchers to invest more attention and research so that early scientific research Transform into productivity, benefit mankind.
