Comprehensive enhancement of mechanical properties of TZM/graphite joints via nanosecond laser fabricated striped structure

In this study, the bonding of a TZM alloy/graphite-brazed joint was improved by fabricating a striped structure on a graphite surface, effectively increasing the surface area ratio and surface roughness of graphite. The typical interfacial microstructure of the joint was TZM/(Ti, Mo)ss/TiNi/TiC/graphite. The shear strength of the joint increased and then decreased with an increase in laser scan distance, reaching a maximum value of 18.1 MPa at a laser scan distance of 90 μm. FEM simulations indicated that the formation of the striped structure optimised the residual stress distribution in the joint, with the stress state at the interface transformed from unilateral tensile stress to alternating tensile-compressive stress. Hence, the formation of the striped structure increased the joining area and optimised the stress distribution of the joints, thereby improving the mechanical properties of the TZM/ graphite-brazed joints.