Effect of thermohydrogen treatment on microstructural evolution and properties of TA15 alloy

Abstract Titanium alloys are widely used in aerospace structural parts. However, they have the characteristics of poor thermal conductivity, high temperature strength and high cutting temperature, which is easy to stick the tools when cutting. Thermohydrogen treatment (THT) is a way that utilizes the reversibility of hydrogen in the titanium alloys to improve the cutting performance. In this article THT process were carried out on TA15 alloy in a vacuum tube furnace. The results shows that the hydrogen content increases with the increase of hydrogen permeation temperature and pressure. As the hydrogen content increases, β phase increases and converts to the hydride δ phase. With the increase of hydrogen content, the cutting force decreases first and then increases. The cutting force is the lowest when the hydrogen content is about 0.3%.