单晶γ-TiAl中孔洞尺寸对裂纹扩展影响的分子动力学模拟  

Effect of Hole Size on Single Crystal γ-TiAl Alloy Crack Propagation Based on Molecular Dynamics Simulation

作　　者：芮执元[1,2] 曹卉[1,2] 罗德春 陈文科[1] 杨利 剡昌锋 Rui Zhiyuan Cao Hui Luo Dechun Chen Wenke Yang Li Yan Changfeng(Lanzhou University of Technology, Lanzhou 730050, China Digital Manufacturing Technology and Application of Key Laboratory of the Ministry of Education, Lanzhou 730050, China)

机构地区：[1]兰州理工大学,甘肃兰州730050 [2]数字制造技术与应用省部共建教育部重点实验室,甘肃兰州730050

出　　处：《稀有金属材料与工程》2017年第9期2505-2511,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51065014);甘肃省自然科学基金(148RJZA008);甘肃省高等学校科研项目(2014A-033)

摘　　要：运用分子动力学方法研究单晶γ-Ti Al合金的裂纹扩展行为,模拟时采用嵌入原子势方法,结合原子轨迹图、能量演化图以及应力-应变曲线,分析不同孔洞尺寸对裂纹扩展过程的影响。结果表明:随着孔洞半径增大,裂纹的启裂应力值减小;裂纹与孔洞结合后,R=0.4001 nm时,孔洞变形后在孔洞边界的中心产生裂纹,沿[100]方向扩展至材料断裂,裂纹扩展中出现子母裂纹传播现象;R=0.8002 nm时,孔洞变形后在一角处产生裂纹,沿[100]方向扩展至材料断裂;R=1.2003 nm时,孔洞变形后在两个角处产生裂纹,沿[110]和[110]方向扩展,[110]方向裂纹扩展中出现子母裂纹传播现象,且边界产生子裂纹并与该方向裂纹汇合后扩展至材料断裂;此外孔洞抑制裂纹扩展。Molecular dynamics method has been applied to research the process of crack propagation of single crystal γ-Ti Al. The atomic trajectory figure,energy evolution and the relationship between stress and strain were obtained to study the hole size effect. The results indicate that the initiation stress decreases with hole size increasing. After the crack combines with the hole,when R=0.4001 nm,crack occurs at the center of hole boundary after hole deformation,and it propagates along the direction of [100] until material fracture,and mother-child model is found; when R=0.8002 nm,crack occurs at one corner after hole deformation,and it propagates along the direction of [100] until material fracture; when R=1.2003 nm,crack occurs at two corners after hole deformation,and it propagates along the direction of [110] and [110],mother-child model is found at the direction of [110],and child crack occurs at boundary which combines with crack in this direction and propagates until material fracture. In addition the crack propagation is inhibited by the hole.

关 键 词：Γ-TIAL合金 分子动力学 裂纹扩展 孔洞尺寸 

分 类 号：TG146.23[一般工业技术—材料科学与工程]