摘要
通过采用Gleeble-1500D热模拟试验机进行超塑性变形试验,研究变形温度和应变速率对置氢TC4合金超塑变形性能的影响,利用XRD,SEM和TEM分析热氢处理改善钛合金超塑性能的机制。结果表明:置氢可降低超塑成形流变应力、变形温度,提高应变速率和m值;但只有适量的氢才有利于改善钛合金超塑性,即存在一个最佳置氢量;置氢0.35%H(质量分数)的TC4合金在800℃和3×10-3s-1条件下仍有一定超塑性。分析表明,置氢钛合金超塑变形过程除晶粒转动和滑动机制外,位错滑移和孪生也作为辅助超塑变形机制。
Influence of deformation temperature and strain rate on superplastic formation （SPF） of Ti-6Al- 4V alloy processed by hydrogenation was studied by u- sing Gleeble-1500D thermal simulator. Mechanism of improving superplasticity of titanium alloy by thermo- hydrogen treatment was analyzed with X-ray diffraction （XRD）, scanning electron microscopy （ SEM ） and transmission electron microscopy （TEM）. The results showed that thermo-hydrogen treatment could not only decrease the superplastic flow stress and deformation temperature, but also increase strain rate and the value of strain rate sensitivity index represented by m . There was optimal hydrogen content for improving the superplasticity of titanium alloy. Though the deforma- tion temperature decreased to 800 C and the deforma- tion rate was 3 ×10-3 s-1, TC4 titanium alloy with 0.35% （mass fraction） hydrogen had superplastic a- bility to a certain extent and the mechanism of super- plastic formation （SPF） was the combined effect of crystal grain rotating, grain boundary sliding supplied with dislocation gliding and twinning deformation.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2009年第4期467-471,共5页
Chinese Journal of Rare Metals
