With the further development of space industry and the continuous exploration of deep space, the performance requirements of spacecraft structural parts for cryogenic materials are further improved. On the one hand, the spacecraft structural materials must have enough strength and toughness and excellent thermal properties at low temperature; On the other hand, considering the complexity of the shape of spacecraft structural parts, the material must have good machinability. Compared with traditional low temperature materials, titanium alloy has higher yield strength at low temperature, more than 3 times of stainless steel, while its density is only 1/4 to 1/2 of stainless steel. In addition, titanium alloy also has a series of advantages such as low thermal conductivity, small coefficient of expansion, no magnetism, so it is very suitable for the application of new low temperature materials in the field of aerospace.
At present, cryogenic titanium alloy has been initially applied in the field of liquid rocket engine, mainly as hydrogen storage tank of hydrogen and oxygen engine, hydrogen pump impeller and other structural materials, greatly improving the thrust-weight ratio, working life and reliability of liquid rocket engine. The biggest problem in the application of low temperature titanium alloy is that the elongation and fracture toughness of titanium alloy are greatly reduced at low temperature, showing obvious low temperature brittleness. Therefore, how to reduce the low temperature brittleness of titanium alloy and improve the toughness and plasticity of titanium alloy at low temperature has become the top priority in the research of low temperature titanium alloy. In order to solve this problem, domestic and foreign scholars have carried out a large number of studies, and found that the low temperature performance of titanium alloys can be effectively improved by reducing the content of C, H, O and other gap elements and reducing the content of aluminum. Through these two methods, a series of new low temperature titanium alloys with excellent properties have been developed at home and abroad.
