Titanium is an important structural metal. Titanium alloys have the characteristics of high strength, good corrosion resistance and high heat resistance. Now, more and more titanium alloys are used in people's lives, not just in the field of aerospace.
Conventional titanium alloys tend to burn alkane under certain conditions, which largely limits their applications. In response to this situation, various countries have launched research on flame-retardant titanium alloys and achieved certain breakthroughs. Ti-1720 developed by the United States, with a nominal composition of 50Ti-35V-15Cr (mass fraction), is a flame-retardant titanium alloy that is not sensitive to continuous combustion and has been used in F119 engines. BTT-1 and BTT-3 are flame-retardant titanium alloys developed in Russia, both of which are Ti-Cu-Al alloys. They have quite good thermal deformation performance and can be used to make complex parts.
Titanium is non-toxic, light in weight, high in strength and has excellent biocompatibility. It is an ideal medical metal material and can be used as implants implanted in the human body. At present,
Ti-6Al-4V alloy is still widely used in the medical field. However, the latter will precipitate a very small amount of vanadium and aluminum ions, which reduces its cell adaptability and may cause harm to the human body. This problem has already attracted widespread attention in the medical field. As early as the mid-1980s, the United States began to develop aluminum-free, vanadium-free, biocompatible titanium alloys for orthopedics. Japan, the United Kingdom, etc. have also done a lot of research work in this area, and have made some new progress. For example, Japan has developed a series of a+β titanium alloys with excellent biocompatibility, including Ti-15Zr-4Nb-4Ta-0.2Pd, Ti-15Zr-4Nb-aTa-0.2Pd-0.20~0.05N, Ti-15Sn-4Nb-2Ta-0.2Pd and Ti-15Sn-4Nb-2Ta-0.2Pd-0.20, the corrosion strength, fatigue strength and corrosion resistance of these alloys are better than Ti-6Al-4V. Compared with a+β titanium alloy, β titanium alloy has higher strength, better incision performance and toughness, and is more suitable for implanting into the human body as an implant. In the United States, five β titanium alloys have been recommended to the medical field, namely Ti-12Mo-Zr-2Fe, Ti-13Nb-13Zr, Ti-15Mo-2.5Nb-0.2Si, TTi-16Nb-9.5Hf and Ti-15Mo. It is estimated that in the near future, this kind of titanium alloy with high strength, low elastic modulus, excellent formability and corrosion resistance is likely to replace the Ti-6Al-4V alloy widely used in the medical field.
