孔洞对含Nb单晶γ-TiAl合金力学性能的影响  

Effects of Voids on Mechanical Property of Single Crystalγ-TiAl Alloys Containing Nb

作　　者：寇佩佩 冯瑞成[1,2] 李海燕[1,2] 李龙龙 王茂茂 祁永年 KOU Peipei;FENG Ruicheng;LI Haiyan;LI Longlong;WANG Maomao;QI Yongnian(School of Mechanical and Electrical Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Digital Manufacturing Technology and Application,the Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学机电工程学院,兰州730050 [2]兰州理工大学数字制造技术与应用省部共建教育部重点实验室,兰州730050

出　　处：《材料导报》2020年第14期14140-14146,共7页Materials Reports

基　　金：国家自然科学基金(51865027,51665030);兰州理工大学红柳一流学科建设项目。

摘　　要：采用分子动力学方法研究了孔洞尺寸、数量以及位置对含Nb单晶γ-TiAl合金力学性能的影响,分析了材料内部的微观缺陷演化及其与材料力学性能之间的关系。结果表明:Nb元素的加入提高了单晶γ-TiAl合金的屈服强度和弹性模量;随孔洞尺寸和数量的增加,含Nb单晶γ-TiAl合金的屈服强度依次减小,这主要是因为孔洞在拉伸过程中充当位错源的作用,它为位错的形核和发射提供了条件;多个孔洞平行于拉伸方向分布时,材料的屈服应力最大,垂直于拉伸方向分布时,材料的屈服应力最小,最容易导致材料失效。The effects of void size,number and position on the mechanical properties of single crystalγ-TiAl alloys containing Nb were studied by mole-cular dynamics method.The relationship between the micro-defect evolution inside the material and the change of the mechanical properties of the material was analyzed.The results indicate that the yield strength and elastic modulus of single crystalγ-TiAl alloys are increased with the addition of Nb element.With the increase of void size and number,the yield strength of single crystalγ-TiAl alloys containing Nb decreases in sequence,which is mainly due to the voids as a dislocation source in the stretching process,which provides conditions for the nucleation and emission of dislocations.When several voids are distributed parallel to the tensile direction,the yield stress of the material is the largest.And when the distribution of the voids perpendicular to the tensile direction,the yield stress of the material is the smallest,which is the most likely to lead to the failure of the material.

关 键 词：Γ-TIAL合金 分子动力学 孔洞 力学性能 位错 

分 类 号：TG146[一般工业技术—材料科学与工程]