置氢Ti-6Al-4V钛合金的热压缩变形行为研究

Deformation behavior in the isothermal compression of hydrogenated Ti-6Al-4V alloy

通过热模拟压缩实验，研究了氢对Ti-6Al-4V钛合金热变形行为的影响。结果表明，置氢可以显著降低Ti-6Al-4V钛合金高温压缩时的流动应力，提高Ti-6Al-4V钛合金的热加工变形速率一个数量级以上，并且明显降低了Ti-6Al-4V钛合金的变形温度。在变形温度760℃～800℃范围内，置氢量为0．4wt％的Ti-6Al-4V钛合金的流动应力最小；在变形温度840℃～920℃范围内，置氢量0．2wt％的Ti-6Al-4V钛合金的流动应力最小。同时，置氢前后Ti-6Al-4V钛合金的变形激活能计算结果表明，置氢量为0．4wt％的Ti-6Al-4V钛合金在α＋β两相区的变形激活能为208．3kJ／mol，与未置氢Ti-6Al-4V钛合金相比降低了316kJ／mol。

Effect of hydrogen on deformation behavior of the Ti-6Al-4V alloy was investigated through isothermal compression. Addition of hydrogen decreases significantly flow stress, improves strain rate of more than one order of magnitude and decreases significantly deformation temperature of the Ti-6Al-4V alloy. The minimum flow stress of Ti-6Al-4V alloy is at a hydrogen content of 0. 4wt% in the deformation temperature range from 760℃ to 800℃, but the minimum flow stress is at a hydrogen content of 0. 2wt% in the deformation temperature range from 840℃ to 920℃. Meanwhile, apparent activation energy for deformation of the Ti-6Al-4V alloy is 208. 3kJ/mol at a hydrogen content of 0.4wt% in α＋β two-phase field, decreasing 316kJ/mol in comparison with that of the Ti-6Al-4V alloy with natural hydrogen.