Titanium alloy is based on titanium to join other elements of the alloy. Titanium has two kinds of homogeneous amorphous: 882 ℃ below the closed hexagonal structure of α titanium, 882 ° C above the body of the heart of the β titanium. Alloy elements according to their impact on the phase transition temperature can be divided into three categories: ① stable α phase, improve the phase transition temperature of the element α stable element 'with aluminum, carbon, oxygen and nitrogen. Aluminum is the main alloy of titanium alloy elements, it is to improve the alloy at room temperature and high temperature strength, reduce the specific gravity, increase the elastic modulus has a significant effect. ② stable β phase, lower phase transition temperature of the elements for the β-stable elements, but also sub-crystal and eutectoid two. The former are molybdenum, niobium, vanadium, etc .; the latter are chromium, manganese, copper, iron, silicon and so on. ③ little effect on the phase transition temperature elements for the neutral elements, zirconium, tin and so on.