Study on the interface formation mechanism and properties of CoCrNi/316L composites prepared by explosive welding

In this study, a CoCrNi/316L composite is prepared via explosive welding. The interface of the CoCrNi/316L composite exhibits a uniform wavy structure with vortices. The formation mechanism of the wavy interface is clarified using smoothed particles hydrodynamics (SPH) simulation, which is also employed to calculate the temperature and strain distribution at the interface during the explosive welding. By correlating the simulated temperature and strain fields at different locations with the experimentally observed grain characteristics, the formation mechanism of various grain types near the interface is analyzed. The CoCrNi matrix consists of ultrafine equiaxed grains formed through dynamic recrystallization (DRX), while the 316L contains coarse grains characterized by high stress due to severe deformation. The vortex zones are primarily composed of columnar grains resulting from crystallization of molten liquid. Nanoindentation test results show that the hardness progressively increases from the matrix to the interface. Notably, the interfacial shearing strength of the CoCrNi/316L composite reaches up to 796 MPa.