Dynamic Shear Mechanical Properties and Microscopic Deformation Characteristics of Laser Cladding IN625 Alloy

Abstract

To reveal the dynamic shear mechanical properties of laser cladding Inconel 625 (IN625) alloy, dynamic shear mechanical properties experiments are conducted on forged specimens and laser cladding specimens by split Hopkinson press bar experimental device. Optical microscopy, scanning electron microscopy, and electron backscattered diffraction (EBSD) are used to characterize the microscopic morphology, crystal orientation, and grain size of laser cladding specimens before and after dynamic shear deformation. In the results, it is shown that the yield strength and shear strength of both forged and laser clad specimens increase with the increase of shear strain rate, reflecting a remarkable strain‐rate‐strengthening effect, and the shear strength of the laser cladding specimen is higher than that of the forged specimen. After dynamic shear loading, the grains in the shear region of the laser cladding specimen are severely deformed, deformation bands appear, and some dendrites are transformed into equiaxed crystal. After shear deformation, the preferred orientation strength of the crystal increases, the small‐size grain and low‐angle grain boundary increase, and a large number of dislocations are formed in the shear region, which dominates the dynamic shear deformation behavior of the material. Dislocation is an important dominant mechanism of dynamic shear deformation.