Asymmetric interlocking and inclined remelting in laser powder bed fusion of horizontally joined AISI 316L–alumina parts

Joining a metal, such as AISI 316L, to a ceramic with a lower coefficient of thermal expansion, such as alumina, presents challenges owing to the residual stress and stress concentration at the interface. Among the general mechanical model for suture interfaces, the triangular shape has demonstrated optimal performance in tensile tests but only moderate performance in three-point bending tests. This paper introduces a series of new asymmetric interlocking geometries designed to incorporate heterogeneous stress states and torsion during the deformation process. Experiments and crystal plasticity simulations using the finite-element and Rietveld methods were conducted to assess the results. The optimal asymmetric crank-like interlocking shape demonstrated high strength and ductility in tension, and it was nearly as effective as the triangular shape. This performance is attributed to significant bending moments, an anchor-like effect at the interface, and the emission of dislocations throughout the geometry. During bending, owing to the torsion distribution along the components, the crank shape exhibits a gradient in dislocation strengthening, a high distribution of hardness, and enhanced self-healing capabilities by oxide fragmentation and crack filling. Additionally, this paper introduces inclined remelting, a technique that can further mitigate common defects in metal–ceramic components and enhance the microhardness of the interface through the formation of a semi-solid flow.