Hot deformation behavior of a near alpha titanium alloy with/without thermal hydrogen processing

Abstract

The true stress-true strain curves of Ti-6Al-2Zr-1Mo-1V alloy with hydrogen were obtained by hot compression test. The microstructures of the alloy before and after thermo-compression were observed. The apparent activation energies of deformation were calculated for the alloy with and without hydrogen. The behavior and mechanism of deformation for hydrogenated Ti-6Al-2Zr-1Mo-1V alloy at high temperature were analyzed. The relationship between hydrogenation time and hydrogen content at 800 ‐ C can be expressed as the equation: CH(t)=1.2i1.2exp(it/120). The true stress-true strain curves of hot compression for Ti-6Al-2Zr-1Mo-1V alloy with hydrogen flrst move down and then move up as hydrogen content increases. Appropriate hydrogen content can reduce the peak of ∞ow stress to minimal value. The apparent activation energies of deformation of the alloy with 0.47% hydrogen content and without hydrogen were calculated as 140 kJ¢mol i1 and 390 kJ¢mol i1 , respectively, at 800 ‐ C and at strain rate 8.3£10 i4 s i1 . The apparent activation energy of deformation increases when the strain rate enhances from 8.3£10 i4 s i1 to 8.3£10 i2 s i1 .