置氢Ti-6Al-4V合金显微组织演变与高温变形行为

Microstructure evolution and high temperature deforming behavior of hydrogenated Ti-6Al-4V alloy

利用Gleeble高温压缩模拟实验研究置氢对Ti-6Al-4V合金微观组织和高温变形行为的影响，并探讨组织与高温塑性的关系。结果表明：适量的氢可显著降低钛合金的高温变形流变应力，Ti-6Al-4V合金氢含量为0．3％时，流变应力降低36％～60％，最小峰值应力对应的氢含量随温度的增加向低氢方向移动，并且在保持相同应力水平下，高温变形温度降低50℃；氢还可以促进钛合金热变形过程中的动态回复和动态再结晶，有利于降低变形抗力，其应力-应变曲线无明显硬化阶段；此外，由于氢引起的高温变形组织变化与在更高温度压缩时所引起的组织变化相当。

The effect of hydrogenation on the microstructure and high temperature deforming behavior of Ti-6Al-4V alloy was investigated by Gleeble thermal simulation test. The correlation between microstructure and high temperature behavior has been explored too. The results show that a certain amount of hydrogen in Ti-6Al-4V alloy can significantly reduce the flow stress of high temperature deformation. Adding 0.3% hydrogen in Ti-6Al-4V alloy allows a reduction of 36%～60% in forging stress and the hydrogen content that corresponds to the minimum flow stress generally decreases when the temperature increases. While keeping the same stress level, the deformation temperature decreases about 50℃. Hydrogen can promote the dynamic recrystallization and dynamic recovery during deformation, as a result, the flow stress may decrease and the true strain-true stress curves of hydrogenated alloy don＇t show hardening stage obviously. Furthermore, the microstructure changes produced by increasing hydrogen content that happens during hot compression at a fixed temperature are equal to that obtained at higher temperature.