Modeling of thermo-mechanical coupling in linear friction welding of Ni-based superalloy

Abstract Thermo-mechanical coupling effect is the core of friction welding, which determines the microstructure evolution and mechanical performance of friction welded joints. However, the studies on thermo-mechanical fields during linear friction welding (LFW) based on rigid/plastic friction pair model in the past cannot reveal the real physical nature correctly. So in this study, the plastic/plastic friction pair model composed of two reciprocating workpieces was established to describe the friction interface condition, in which the modified Coulomb's model was used to calculate the friction stress. Transient friction heat generation and volumetric heat generation by plastic deformation were used to calculate the heat input. Results showed interface temperature varied with time periodically. Plastic deformation heat during LFW had significant influences on temperature and plastic deformation. Stress field distribution changed alternately with the reciprocate motion, and the variation of joint internal stress reached the quasi-steady state as well as thermal equilibrium. Also, the influences of welding parameters were studied quantitatively. Finally, simulated results were well validated by experimental temperature and shortening histories, as well as microstructure observation. The findings in these studies can help to understand the linear friction welding process, and provide a theoretic foundation on the control of linear friction welding process.