含孔洞缺陷的单晶α-Ti单轴拉伸下的微观变形机理及力学性能  

Micro Deformation Mechanism for the Void Defects Embedded in a Single Crystal α-Ti in Tension and Its Effect on Mechanical Properties

作　　者：丁军 汪建 黄霞 王路生 赵昊男 宋鹍 DING Jun;WANG Jian;HUANG Xia;WANG Lusheng;ZHAO Haonan;SONG Kun(College of Mechanical Engineering,Chongqing University of Technology,Chongqing 400054)

机构地区：[1]重庆理工大学机械工程学院,重庆400054

出　　处：《材料导报》2018年第18期3171-3180,共10页Materials Reports

基　　金：国家自然科学基金委员会与中国工程物理研究院联合基金(U1530140);重庆市基础与前沿研究计划项目(CSTC2016JCYJA0517;CSTC2017JCYJAX0357);重庆市教育委员会科学技术研究项目(KJ1709224)

摘　　要：采用分子动力学方法模拟了含球形孔洞的单晶α-Ti在单轴拉伸载荷作用下孔洞的生长过程和微观力学特性。研究表明,低应变率作用下,材料应力-应变曲线出现四个不同响应阶段:初始线性阶段、急剧下降阶段、快速增长阶段、快速下降至平稳阶段。由模拟结果原子构型图观察得知,对于孔洞赤道附近的锥面〈a〉型滑移系{1101}〈1120〉和{1011}孪生是孔洞生长的主要形式。通过研究模型尺寸、应变率、孔洞体积分数对单晶α-Ti材料力学性能的影响,结果表明:该材料的初始屈服应力随着模型尺寸、孔洞体积分数的增加而减小,随着应变率的增加而增大;杨氏模量只与孔洞体积分数有关,并随着孔洞体积分数的增大而减小。The void growth process and microscopic mechanical properties of a single crystalα-Ti cube containing a spherical void in uniaxial tension loading were investigated by molecular dynamics simulation.The results showed that the stress-strain curves of the material appeared four different stages at the low strain rate:the initial linear stage,the sharp drop stage,the rapid increase stage and the rapid drop to the steady stage.Microstructure observation from MD results also indicated that the pyramidal〈a〉slip system{11 01}〈112 0〉and{101 1}twinning near the equator area of the void was the main form of void growth.The effects of specimen size,strain rate,void volume fraction on mechanical properties of single crystalα-Ti materials were studied,the result showed that the initial yield stress of the materials decreased with the increase both in specimen size and void volume fraction,but increased with the increase in strain rate;the Young’s modulus of the material depended only on the void volume fraction which decreased with the increase of the void volume fraction.

关 键 词：分子动力学 孔洞生长 孪生变形 堆垛层错 Α-TI 

分 类 号：TG146.1[一般工业技术—材料科学与工程]