A thermodynamic analytical model based on entropy production for predicting the grain size and yield strength of the joint formed by continuous drive friction welding

A self-consistent analytical model for predicting qualities of a joint welded by continuous drive friction welding (CDFW) was developed based on the Onsager-Ziegler maximum entropy production principle (OZ-MEPP), dislocation kinetics, and the CDFW analytical model developed in our previous work. The microstructure and mechanical properties of the friction-welded joint can be predicted by the model requiring only the geometric, thermal, and physical parameters of the specimens without any assumed or premeasured response parameters. The accuracy of the model was verified by the microstructure and properties of the joints fabricated by CDFW of 304 stainless steel. The results indicated that the model is feasible and effective for forecasting the grain size and yield strength of the joints, which means it is possible to use a single thermodynamic state function, i.e., entropy production, for predicting the qualities of a CDFW joint, especially when the joined alloy has a simple phase composition.