高纯钛压缩孪生行为研究

利用背散射电子衍射(EBSD)技术对高纯钛形变组织中同一个晶粒内部出现的{1122}和{1124}压缩孪生进行了研究。结果表明:{1124}孪晶总是伴随{1122}孪晶在同一晶粒中产生,在变形组织中没有发现单独存在的{1124}孪晶;这种极少出现的{1124}压缩孪晶主要由{1122}孪晶与传统晶界或{1122}孪生变体之间交互作用改变了局部应力状态而诱发的。在同一个晶粒中,由{1122}孪晶诱发的{1124}孪晶更倾向于同其中一个{1122}孪生变体具有相同的转轴。此外,根据晶体对称性及相同晶粒中{1122}和{1124}孪晶之间的取向关系,{1122}和{1124}孪晶之间可发生孪晶反应并形成4种不同类型的孪晶反应界面。

Study of Compressive Twinning Behavior in High-purity Titanium

Compressive twinning behavior in high-purity titanium was studied by electrical back-scattered diffraction (EBSD) techniques. The results show that {11-24} twins are always accompanied with {11-22} twins in some specific grains, and individual {11-24} twin is not observed in microstructure of the deformed sample. The formation of {11-24} twin is attributed to the changes of local stress states, which induced by the {11-22}-{11-22} twin variants interactions or {11-22} twin interactes with the grain boundaries. The {11-22} and {11-24} twins tend to share a common rotation axis with one of the {11-22} twin variant within an initial grain. In addition, due to the crystal symmetry and the orientation relationships between {11-22} and {11-24} twins, interactions between {11-22} and {11-24} twins inevitably occur, which results in four different types of {11-22}-{11-24} twin junctions.