α-Ti中变形孪晶的电子显微学研究

α-Ti中变形孪晶的电子显微学研究

饶　奎，刘佩银，倪　颂^*

（中南大学 粉末冶金国家重点实验室，湖南 长沙 410083）

摘　要　　本文利用电子显微表征手段，对α-Ti在室温高应变速率冲击变形条件下产生的孪晶微观结构进行了研究，包括共格孪晶界、台阶及孪晶的尖端特征。结果表明，{}与{}拉伸孪晶中最常见的台阶分别为两层和单层，对应的孪生位错分别为b₂和b₁；{}和{}压缩孪晶中最常见的台阶为两层和三层，对应于b₂和b₃孪生位错，这些孪生位错在孪晶面内的滑动控制着孪晶的扩张与收缩；此外，{}孪晶可以通过B/P或P/B界面向基体和孪晶内部发射FCC纳米条带来释放局域的应力集中。

关键词　　α-Ti；变形孪晶；孪生位错；电子显微表征

中图分类号：TG146.2⁺3; TG115.21⁺5.3　　文献标识码：A Doi:10.3969/j.issn.1000-6281.2025.05.006

Electron microscopy investigation on deformation twins in α-Ti

RAO Kui, LIU Peiyin, NI Song^*

(State Key Laboratory of Powder Metallurgy, Central South University, Hunan Changsha 410083, China)

Abstract　　This study studied the microstructures of twins activated in α-Ti under high strain rate impact deformation at room temperature using transmission electron microscope. Detailed analysis focused on coherent twin boundaries, step structures and twin tip characteristics. The results revealed that most common steps in the {} and {} tensile twins were two-layer and single-layer steps, respectively, corresponding to twinning dislocations b₂ and b₁. For the {} and {} compression twins, the dominant steps are two-layer and three-layer, associated with b₂ and b₃ twinning dislocations, respectively. The motion of these dislocations within the twin planes governed the expansion and contraction of twins. Furthermore, the {} twins are capable of relieving local stress concentrations by emitting FCC nanobands into both the matrix and the twin interior via B/P or P/B interfaces.

Keywords　　α-Ti; deformation twins; twinning dislocations; electron microscopic characterization

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