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

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. © All right reserved.