高锰TWIP钢中形变孪晶界缺陷的电镜表征研究  

Electron microscopy characterization of the defects of deformation twin boundaries in high manganese TWIP steels

作　　者：谢盼 伍翠兰[4] 陈江华[1,2,3,4] XIE Pan;WU Cui-lan;CHEN Jiang-hua(Pico Electron Microscopy Center,Innovation Institute for Ocean Materials Characterization Technology,Center for Advanced Studies in Precision Instruments,Hainan University,Haikou Hainan 570228;Key Laboratory of Pico Electron Microscopy of Hainan Province,Hainan University,Haikou Hainan 570228;School of Materials Science and Engineering,Hainan University,Haikou Hainan 570228;Center for High-resolution Electron Microscopy,Hunan University,Changsha Hunan 410082,China)

机构地区：[1]海南大学精密仪器高等研究中心,海洋材料表征技术创新研究院,皮米电镜中心,海南海口570228 [2]海南省皮米电子显微学重点实验室,海南海口570228 [3]海南大学材料科学与工程学院,海南海口570228 [4]湖南大学高分辨电镜中心,湖南长沙410082

出　　处：《电子显微学报》2023年第5期596-604,共9页Journal of Chinese Electron Microscopy Society

基　　金：湖南省自然科学基金面上项目(No.2022JJ30146);海南省自然科学基金面上项目(No.223MS008).

摘　　要：通常认为孪晶界是完全共格和无缺陷的,但变形过程中产生的孪晶界往往带有很多缺陷。本文通过高分辨透射电镜观察研究了高锰孪生诱发塑性(twinning induced plasticity,TWIP)钢中形变孪晶界的缺陷特征。结果表明,高锰TWIP钢中形变孪晶界的缺陷包括界面原子台阶、9R结构单元和由于位错和孪晶界相互作用产生的高密度位错。与传统认为9R结构由Σ3{112}非共格孪晶界的分解产生不同,形变孪晶界上9R结构单元由晶界直接发射不全位错形成。位错和孪晶界的交互作用造成了孪晶的退化,并在孪晶界附近产生了大量位错,包括高密度的全位错和Frank分位错。基于形变孪晶界缺陷的电镜表征,分析和总结了高锰TWIP钢的强韧化机制。Twin boundaries(TBs)are usually considered to be coherent and perfect.Here we report that deformation twins in twinning induced plasticity(TWIP)steels are often defective with steps,9R structures and massive dislocations formed by the dislocation-TB interactions.These imperfections are finely identified by high-resolution transmission electron microscopy(HRTEM).It is found that some 9R structures can be directly produced by the glide of Shockley partial dislocations(SPDs)emitted from boundaries,which differs from the traditional 9R phase created by the dissociation ofΣ3{112}incoherent TB.Dislocation-TB interactions result in de-twinning at the both sides of the primary deformation twin and produce different types of dislocations near the TBs,including high densities of full dislocations and the Frank partial dislocation.Base on the analysis of various defects at TBs,the mechanism of twinning-induced plasticity and strain hardening is summarized in TWIP steels.

关 键 词：TWIP钢 形变孪晶 位错 9R结构 

分 类 号：TG142.11[一般工业技术—材料科学与工程] TG142.33[金属学及工艺—金属材料] TG115.215.3[金属学及工艺—金属学]