Element diffusion model with variable coefficient in bimetallic bonding process

The bimetallic bonding mechanisms including macroscopic deformation, microstructure evolution and element diffusion were investigated by using bimetallic hot compression tests of X65/316L. An element concentration diffusion model with a variable coefficient was proposed to determine the element concentration in the metallurgical bonding transition zone (MBTZ). Diffusion distance, strain, deformation temperature and holding time were taken into account in the model. A finite element model of the clad pipes hot extrusion process to investigate the element diffusion behavior in the MBTZ was developed by the proposed diffusion model. The concentration predicted by the proposed model have a good agreement with the experimental results and the proposed model is more accurate than the reference model.