An innovative approach to enhancing strength and ductility in cold spray 3D printing through engineered heterogeneous laminate microstructures

Abstract

Achieving an ideal balance of strength and ductility in 3D-printed low-pressure cold spray materials is highly desirable yet remains a significant challenge. This paper introduces a dual heterogeneous laminated Cu/CuCrZr composite structure, characterized by varying properties between a soft and hard domains, manufactured through low-pressure cold spray followed by heat-treatment. The tailored heterogeneous Cu/CuCrZr microstructure features alternating coarse and fine grains, resulting in a hetero-deformation-induced hardening, caused by the mechanical incompatibility between the coarse grain Cu and fine grain CuCrZr layers, leading to an improvement of work hardening and increase of ductility. This performance is largely attributed to the well-bonded particles and hetero-deformation-induced (HDI) strengthening during plastic deformation. The strengthening effect is due to the accumulation of a substantial number of geometrically necessary dislocations (GNDs) at the heterogeneous interface, which enhances work-hardening and simultaneously boosts both the strength and ductility of the layered structure. The engineered laminate showed 205% and 115% improvement in strength and ductility compared to Cu and 10% and 28% improvement when compared to CuCrZr.