置氢TC21合金超塑性研究

Research on Superplasticity of Hydrogenated TC21 Alloy

利用CMT4104电子万能试验机研究了置氢TC21合金在不同温度和应变速率下的超塑性。结果表明,随氢含量增加,TC21合金的流动应力先降低后升高,存在一个最佳变形量。置氢后大部分条件下伸长率随氢含量的增加而降低,但氢含量为0.1wt%时,在880℃,1×10-3s-1条件下变形,获得了1010%的最大伸长率。TEM观察发现,当氢含量较低时,TC21-xH合金主要的超塑变形机制为位错攀移和滑移协调的相界/晶界滑移;当氢含量较高时,由于氢降低了TC21合金的相变点,变形在单相β相区进行,变形机制为由扩散促进位错恢复和攀移的晶界滑动机制。

The superplasticity of TC21 with hydrogenation under different temperatures and strain rates was studied by CMT 4104 universal testing machine. The results show that the flow stress of TC21 alloy decreases first and then increases with the increase of hydrogen content. The optimum content of hydrogen is obtained. However, the elongation decreases after hydrogenation under most test conditions. The maximum elongation of 1010% is obtained at 880 ℃, 1 × 10.3 s-1 under the hydrogen content of 0.1%. TEM observation shows that the superplastic deformation mechanism is phase/grain boundary sliding accommodated by dislocation climbing and sliding at low hydrogen content. When hydrogen content is high, the mechanism is grain sliding of dislocation recovery and climbing promoted by diffusion.