摘要
利用重复冲击变形技术对比研究了α钛合金Ti-2Al-2.5Zr和亚稳β钛合金Ti-10V-2Fe-3Al变形过程中的微观组织演化及纳米晶的形成机制。金相形貌、X射线衍射及透射电镜观察显示,对于Ti-2Al-2.5Zr合金,塑性变形先后经历了形变孪生、位错活动、剪切等3个过程。与之相反,对于Ti-10V-2Fe-3Al合金,马氏体相变主导着合金的变形。相变分割、剪切及逆向马氏体相变持续贡献于合金的晶粒细化。同时发现,尽管变形到应变量1.2时两类合金组织内均出现纳米晶,但是大量的透射形貌观察显示Ti-10V-2Fe-3Al合金中生成的纳米晶晶粒尺寸更小,纳米晶区域更大。这表明,变形过程中激活马氏体相变可加速材料的晶粒细化。
The microstructural evolution and formation mechanism of nanograins in Ti-2Al-2.5Zr α-titanium alloys and Ti-10V-2Fe-3Al metastable β-titanium alloys subjected to multi-impact process at ambient temperature were investigated using optical microscopy, X-ray diffraction and transmission electron microscopy.The results show that deformation twinning, dislocation activities and shear banding successively dominate plastic deformation in Ti-2Al-2.5Zr alloy.In contrast, deformation-induced martensitic phase transformation becomes prevalent in Ti-10V-2Fe-3Al alloy.Martensitic subdivision, shear banding and reverse martensitic transformation contribute to grain refinement.Moreover, nanograins are finally achieved in both titanium alloys at a strain of 1.2, but grain refining efficiency is more significant in Ti-10V-2Fe-3Al alloy.The accelerated grain refinement could be attributed to the assistance of martensitic phase transformation.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第7期1601-1606,共6页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(51301127)
National Key Basic Research Program of China('973'Program)(2014CB644002)
Natural Science Basic Research Plan in Shaanxi Province of China(2014JQ6205)
the Fundamental Research Funds for Central Universities of China(xjj2014126)
关键词
钛合金
重复冲击变形
马氏体相变
形变孪生
纳米晶
titanium alloys
multi-impact process
martensitic transformation
deformation twinning
nanograins
