亚稳β型Ti-25Nb-25Ta合金{332}<113>变形孪晶交互作用的电子显微研究
王宇轩，孙 威*亚稳β型Ti-25Nb-25Ta合金{332}<113>变形孪晶交互作用的电子显微研究
王宇轩，孙 威*
（北京工业大学固体微结构与性能研究所，北京 100124）
摘 要 本文利用TEM（透射电子显微镜）的表征方法，对亚稳β型Ti-25Nb-25Ta合金塑性变形过程中{332}<113>孪晶交互作用区域的局域变形结构进行了细致的表征和分析。结果表明：入射孪晶撞击到阻碍孪晶形成截停组态可以产生强交互作用，导致局域孪晶取向及结构的明显变化。一方面入射孪晶的单侧{332}孪晶界由于受到高应力的影响逐渐向低能的{112}孪晶关系过渡，与之对应的孪晶界退缩，使得{332}<113>孪晶界回撤区域成为取向与基体相差13°~16°的过渡区。另一方面在交互作用区域高应力的作用下，在交互作用界面附近的孪生区域形成了{332}<113>二次孪晶，{112}<111>孪晶及扭折带。
关键词 亚稳β钛合金；{332}<113>孪晶；交互作用；应力协调行为；TEM
中图分类号：TG146.2+3；O762；TG115.21+5.3 文献标识码：A doi:10.3969/j.issn.1000-6281.2019.04.003
Electron microscopy characterization of the interaction between {332}<113> deformation twins in a metastable β Ti alloy
WANG Yu-xuan, SUN Wei *
(Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China)
Abstract Local deformation structures related to the interaction between two {332}<113> twin variants in a deformed metastable β-Ti-25Ta-25Nb alloy have been investigated by means of transmission electron microscopy. The results show that the incident twin impinging on an obstacle twin can produce a strong interaction which can bring about obvious local variations in both orientation and structure. It has been observed that the unilaterally curved boundary caused by the local shrinkage of the incident twin exhibits a gradual transition in orientation from a {332} twinning relationship to near a {112} one, and that a transition region having a misorientation of 13°-16° with respect to the matrix can be formed due to the shrinkage. On the other hand, {332}<113>and {112}<111> types of secondary twins along with kink bands can also be formed in the twinned regions close to the twin-twin interaction interface to accommodate high local stress occurring there.
Keywords metastable β titanium alloy; {332}<113> deformation twinning; twin-twin interaction; TEM
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