Evolution of microstructure and intervariant boundaries of phase in electron beam melted and heat-treated Ti-6Al-4V alloy

• 作者: Ming Wang Hao-Qing Li Hong Guo Liu Feng Shu-Yu Liu Xiao-Ying Fang
• 来源期刊: 稀有金属（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: ORIGINAL ARTICLES
• 页码范围: 2118-2126
• 页数: 9页
• 语种: 英文

摘要

It is important to understand the correlation between grain morphology and intervariant boundaries of the α phase after heat treatment below β transus of the electron beam melted (EBMed) Ti-6Al-4V alloy.Scan-ning electron microscopy (SEM) and electron backscatter diffraction (EBSD) analysis have shown about 99％ α phase and 1％ β phase in the heat-treated samples when the temperature rises to 950 ℃.Four distinct types of α grain morphology have been found:allotromorphous α,rela-tively coarse α plate,large precipitation α and granular α.A single peak of the intervariant boundary with the misorientation of 60°/[11(2)0]associated with Burgers ori-entation relationship (OR) was found in the allotromor-phous α colony.Multiple intervariant boundaries mixed with a fraction of general high-angle grain boundary(GHABs,not Burgers OR) were present in the relatively coarse α plate colony.Almost only low-angle grain boundaries (LABs) with the misorientation of ＜ 5° were found in the large precipitation α grains.β phase tends to distribute around the boundaries of relatively coarse α plates.It suggests that different formation mechanisms are involved in the distinct types of α grain morphology.