Effect of hydrogen on the superplasticity of Ti40 alloy with large grains

Abstract

Thermohydrogen processing (THP) is an attractive approach which uses hydrogen as a temporary element in titanium alloys to modify the microstructure/mechanical properties and workability. In this article, the influence of hydrogen on the superplasticity of single β phase Ti40 (Ti–25V–15Cr–0.2Si) alloy with hydrogenation had been investigated in the temperature range of 840–920 °C and strain rate of 5 × 10 −4–1 × 10 −2 s −1. The maximum elongation of 478% was obtained at 920 °C, 5 × 10 −4 s −1 with 0.3 wt.% H. A significant refinement of average grain size in Ti40– xH alloys during superplastic deformation was found and the grain sizes became much finer with the increase of hydrogen content. The superplastic deformation mechanism of Ti40– xH alloy with large grains could be explained by dynamic recovery and recrystallization.