Gutierrez-Urrutia Ivan, Li Cheng-Lin, Ji Xin, Emura Satoshi, Tsuchiya Koichi
National Institute for Materials Science, Tsukuba, Japan.
Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
Sci Technol Adv Mater. 2018 Jun 7;19(1):474-483. doi: 10.1080/14686996.2018.1475824. eCollection 2018.
We have performed quantitative analysis of {332}〈113〉 twinning in a β-Ti-15Mo (wt.%) alloy by scanning electron microscopy and electron backscattering diffraction (EBSD). Microstructure-twinning relations were evaluated by statistical analysis of the evolving twin structure upon deformation at room temperature. Our analysis reveals that at the early stages of deformation ( < 1.5 to 2.0%), primary twinning is mainly determined by the applied macroscopic stress resolved on the twin system. Most of the primary twins (70-80% of the analyzed twins) follow Schmid's law with respect to the macroscopic stress, and most of the growth twins ( 85% of the analyzed twins) correspond to the higher stressed variant. In the grain size range studied here (40-120 μm), we find that several twin parameters such as number of twins per grain and number of twins per grain boundary area exhibit grain size dependence. We ascribe these effects to the grain size dependence of twin nucleation stress and apparent critical resolved shear stress for twinning, respectively.
我们通过扫描电子显微镜和电子背散射衍射（EBSD）对β-Ti-15Mo（重量百分比）合金中的{332}〈113〉孪晶进行了定量分析。通过对室温下变形过程中孪晶结构演变的统计分析，评估了微观结构与孪晶之间的关系。我们的分析表明，在变形的早期阶段（<1.5%至2.0%），初次孪晶主要由孪生系统上分解的外加宏观应力决定。大多数初次孪晶（约占分析孪晶的70-80%）遵循施密德定律与宏观应力相关，并且大多数生长孪晶（约占分析孪晶的85%）对应于应力较高的变体。在此处研究的晶粒尺寸范围内（40-120μm），我们发现几个孪晶参数，如每个晶粒的孪晶数量和每个晶界面积的孪晶数量，表现出晶粒尺寸依赖性。我们分别将这些效应归因于孪生形核应力和孪生表观临界分切应力的晶粒尺寸依赖性。
