NiCrFe焊缝金属的晶界形貌和晶界MC碳化物对局部变形行为的影响  

Effect of Grain Boundary Morphology and MC on Plastic Deformation Behavior of NiCrFe Weld Metal: Crystal Plasticity Finite Element Analysis

作　　者：周辉[1,2] 王培[1,2] 陆善平 ZHOU Hui;WANG Pei;LU Shanping(Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang,110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院核用材料与安全评价重点实验室中国科学院金属研究所,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《材料研究学报》2019年第11期801-808,共8页Chinese Journal of Materials Research

基　　金：中科院重点部署项目(ZDRW-CN-2017-1);江苏省重点研发计划(BE2018113)~~

摘　　要：采用晶体塑性有限元方法研究了NiCrFe焊缝金属中晶界形貌和晶界MC碳化物对局部变形行为的影响。结果表明,试样中的弯曲晶界促进其周围基体中滑移系的开动,进而促进塑性变形均匀分布。由于晶界碳化物MC与基体的临界分剪切应力和硬化行为的差异显著,碳化物承担较高的应力而发生较小的塑性变形。碳化物与基体界面处不连续的应力分布加剧了二者变形的不协调性,使裂纹在MC与基体界面处萌生。焊缝金属中的弯曲晶界和晶界碳化物MC,对高温失塑裂纹的作用相反。为了降低高温失塑的影响,在工程实践中应该在尽量减少MC的情况下得到弯曲晶界。Effect of grain boundary morphology and carbide precipitate on local heterogeneous plastic deformation of a NiCrFe weld metal were investigated by the crystal plasticity finite element method.Results show that the plastic deformation behavior is more homogeneous for the sample with tortuous grain boundaries rather than those with straight grain boundaries, since the tortuous grain boundary can promote the activation of slip systems around it more easily. Owning to the significant differences in the critical resolved shear stress and hardening behavior between the MC carbide and matrix, the carbide has much higher stress and lower strain compared with the matrix. The discontinuous stress distribution at the interface between the carbide and matrix may induce fracture initiation during the deformation. The tortuous grain boundaries and MC precipitates have the opposite effect on the ductility, dipping and cracking of the weld metal. Therefore, it should be tried to obtain the weld metal with tortuous grain boundaries while minimizing MC precipitates for engineering application.

关 键 词：金属材料 高温失塑裂纹 晶体塑性 晶界形态 MC 

分 类 号：TG404[金属学及工艺—焊接]