Low-temperature high-strength titanium alloy with excellent welding performance

Abstract

The invention discloses a low-temperature high-strength titanium alloy with excellent welding performance. The low-temperature high-strength titanium alloy consists of the following components in percentage by mass: 1.0-3.0% of W, 14.0-16.0% of Zr and the balance of titanium and inevitable impurities. The Zr element and the W element are added into the titanium alloy, the adding amount and the total adding amount of the two elements are controlled, it is effectively guaranteed that the titanium alloy has the good low-temperature strength, and the adverse effect on the plasticity of the titanium alloy is reduced; by means of reasonable matching of the two alloy elements of W and Zr, the titanium alloy has the plasticity of 15% or above under the room temperature condition, the good cold and hot machining capacity and welding performance and the uniform and stable structure, can be machined into pipes, bars, plates and the like of various specifications, meets the engineering batch production requirement and has wide application in the aviation field of liquid rocket engines and the like.

Description

technical field [0001] The invention belongs to the technical field of titanium alloy materials, in particular to a low-temperature high-strength titanium alloy with excellent welding performance. Background technique [0002] Titanium alloys have been used on a large scale in the aerospace field. Replacing traditional steel structures with titanium parts has greatly improved the thrust-to-weight ratio of rocket engines, increased rocket launch capabilities and equipment reliability. my country's high-thrust rockets mainly use liquid engines, especially the Long March 5 series rockets currently in use. The important components of the liquid hydrogen system of the first- and second-stage hydrogen-oxygen engines are all made of titanium alloys. With the further development of the lunar exploration project and the Mars exploration program, the demand for heavy-lift and high-thrust rocket engines has become more urgent, and higher requirements have also been placed on the thrust...

AI Technical Summary

Problems solved by technology

Different from the simple annealing process of traditional α-titanium alloys, this alloy needs to adopt a complex graded slow cooling and heat treatment process of 5°C to 25°C below the α-β transition temperature to achieve the above-mentioned performance control. The production efficiency is low, and it is close to the phase transition point. The heat treatment temperature leads to severe annealing deformation and low yield, which is not conducive to the realization of large-scale engineering preparation of materials

[0004]The patent of authorized notification number CN 103627928B discloses a Ti-Al-Nb-Mo series low-temperature high-strength two-phase titanium alloy, the low-temperature strength can reach more than 1400MPa at 20K, However, its yield strength is only 1100MPa, and its safety factor is low when used as a structural part.

At the same time, the welding operability and performance stability of welded joints of α + β two-phase titanium alloys are obviously insufficient compared with α-type titanium alloys. As a typical two-phase titanium alloy, this alloy is prone to metastable formation during welding. The phase leads to a decrease in the plasticity of the welded joint, resulting in a decrease in the safety of the material in use

In order to ensure low-temperature performance, the alloy needs to be double annealed before the finished product. This annealing process is more complicated than the conventional heat treatment process, and it is not suitable for the promotion and use in the field of liquid rocket engines.