Medical titanium alloy

Compared with other medical metal materials, the most significant performance characteristics of titanium alloy are small density, low elastic modulus value, about half of other medical metal materials, the density is close to human hard tissue, so it is widely used in the field of orthopedics. Pure titanium was first used in organisms in the United States and Britain in the 1950s. In 1973, Beijing General Research Institute for Non-ferrous Metals cooperated with Tianjin Orthopaedic Medical Instrument Factory to produce 300 titanium artificial femurs and hip joints for clinical use. Later, it was found that the performance of Ti-6Al-4V alloy is better than pure titanium, the biocompatibility of Ti-6Al-4V alloy is better than stainless steel and CoCrMo alloy, the corrosion resistance of Ti-6Al-4V alloy is good, the elastic modulus is close to the bone, and the density of Ti-6Al-4V alloy is light (4.51g/cm3), can be used in the manufacture of artificial joints and orthopaedic internal fixation devices. Therefore, it has been widely used as human implant material.

From the first (α+β) biphase titanium alloy Ti-6Al-4V to the second (α+β) biphase titanium alloy Ti-5Al-2.5Fe, Ti-6Al-7Nb, the comprehensive mechanical and technological properties of the medical titanium alloy have been improved significantly, and the toxic element V to human body has been removed. The new (α+β) Ti-15Zr alloy and Ti-15Sn alloy have both vanadium and aluminium removed. In recent years, some new titanium alloys, mainly β alloy, have been developed to reduce the elements that are harmful to human body and effectively improve the biocompatibility of titanium alloy. The newly developed biomedical titanium alloys mainly include:

(1) (α+β) titanium alloy

(2) β type titanium alloy

The influence of Al and V elements is reduced or eliminated in the new titanium alloy, and zirconium, niobium, tantalum, stannum and so on are used as alloying elements to improve the mechanical properties, corrosion resistance and biocompatibility of titanium alloy. For example, Ti-13Nb-13Zr is a new type of biological implant titanium alloy developed in the United States, which improves the compatibility with organisms, and has high strength and excellent corrosion resistance. This new alloy diffuses hardening at 500℃ to produce a kind of layered titanium oxide ceramics, which is very strong and smooth, and can be used as bone connecting parts. Recently, Japanese researchers on the basis of the original titanium by adding Pd, Ta, Nb, Zr and oxygen and nitrogen elements to improve the performance, developed a good cell capacitance, corrosion resistance, high room temperature strength and fatigue strength Ti-15Zr-4Nb-4Ta-0.2Pd-0.2O-0.05N titanium alloy. It is expected to be the next generation of biological alloys, but large clinical trials are needed.

In the future development of medical metal materials, according to China's resource advantages, continue to improve and improve the comprehensive mechanical properties of titanium alloy and process properties, give full play to the advantages of medical titanium alloy is still an aspect that can not be ignored. According to the research status of metal implant materials, pure titanium and its titanium alloy have incomparable advantages over other materials, especially the new β -titanium alloy developed in recent years. Therefore, the development and research of new β titanium alloy which is more suitable for clinical application can be regarded as a major development direction of metal implant materials for human body. The further research trend of biomedical titanium alloys is to further study the influence of elements on the microstructure and properties of titanium alloys to improve their comprehensive mechanical properties and process properties. The correlation between biological compatibility test and clinical test of titanium alloy in vitro and in vivo was studied to provide basis for the development of new medical titanium alloy. In addition, new processes and technologies can be used to develop surface modification and functional gradient materials.