Preparation of nano-Al2O3 dispersion strengthened coating via coating-substrate co-sintering and underwater shock wave compaction

Abstract

Abstract This paper aims at developing a process technology to fabricate an aluminum dispersion strengthened coating on a copper substrate. First, nanostructured Cu–Al 2 O 3 powder was prepared by hydrogen-reduction of mechanical alloyed Cu and Al 2 O 3 mixed powders. Low-density coating was then achieved through die pressing and pre-co sintering. Finally, dynamic consolidation by underwater shock wave was used to densify the Cu–Al 2 O 3 sintering body, ensuring strong bonding between the coating and substrate. The compressing process was simulated using the commercially available package LS-DYNA. Numerical simulation gave deformation of the coating layer and pressure distribution during the compressing process. Microstructure characteristics indicate that the coating layer has a uniform and fine-grained composite structure and a strong surface bonding between coating layer and copper substrate. The fracture surface, analyzed by SEM, showed intergranular fracturing. Measurement of hardness showed a high hardness value, indicating sound mechanical properties of the coating layer. This method has thus been proven feasible for preparation of aluminum dispersion strengthened coating on copper substrate.