片层厚度对双相TiAl合金力学性能影响的纳米压痕研究  

Effect of Lamellar Thickness on Mechanical Properties of Dual-Phase TiAl Alloy by Nanoindentation

作　　者：刘兴华 芮执元[1,2] 付蓉[1] 曹卉[1] 文洮[3] 剡昌锋[1,2] Liu Xinghua;Rui Zhiyuan;Fu Rong;Cao Hui;Wen Tao;Yan Changfeng(School of Mechanical and Electrical Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Gansu Computing Center,Lanzhou 730030,China)

机构地区：[1]兰州理工大学机电工程学院,甘肃兰州730050 [2]兰州理工大学有色冶金新装备教育部工程研究中心,甘肃兰州730050 [3]甘肃省计算中心,甘肃兰州730030

出　　处：《稀有金属材料与工程》2022年第2期629-636,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51865027)。

摘　　要：为研究纳米压痕过程中片层厚度和γ/α_(2)相界对双相TiAl合金变形行为及力学性能的影响,针对5种不同厚度的双相TiAl合金模型,采用分子动力学的方法模拟计算了金刚石压头以垂直于γ/α;相界方向分别压入γ和α;相的纳米压痕过程。结果表明:材料的硬度随片层厚度的减小而增大,当片层厚度减小至7nm时,材料的硬度达到最大值,进一步减小片层厚度时,材料的硬度反而减小。材料的弹性模量也会随片层厚度的变化而改变,与硬度呈现正比关系。此外,在纳米压痕过程中,压头压入γ相时,变形行为以{111}面的层错为主,γ/α_(2)相界会阻碍位错的运动;压头压入α;相时,变形行为以(0001)基面的堆垛层错为主,基面上Shockley不全位错的运动会导致材料表面产生相变,且棱柱面滑移被激活。In order to investigate the effects of lamellar thickness and γ/α_(2)interface on the deformation and mechanical properties of dual-phase TiAl alloy during nano-indentation process, molecular dynamics method was used to simulate the nano-indentation process of γ and α_(2)phases with diamond indentation perpendicular to γ/α_(2)interface for five kinds of dual-phase TiAl alloy models. The results show that the hardness of the material increases with the decrease of the lamellar thickness. When the lamellar thickness decreases to 7 nm, the hardness of the material reach the maximum value. However, when the lamellar thickness further decreases, the hardness of the material decreases. The elastic modulus of the material changes with the thickness of lamellar and is proportional to the hardness. In addition, the deformation behavior of γ phase in the nano-indentation process is mainly the stacking fault of {111} plane, and the γ/α_(2)interface can effectively hinder the dislocation movement. The deformation behavior of α_(2)phase is mainly the stacking fault of(0001) base plane. The Shockley partial dislocation motion formed on the base plane leads to the phase transformation on the material surface. The prismatic plane slip system is activated.

关 键 词：片层厚度 双相TiAl合金 力学性能 纳米压痕 分子动力学 

分 类 号：TG146.23[一般工业技术—材料科学与工程]