Plasma Spray Joining of Aluminum Matrix Composites Using Osprey Composite Powder

Abstract

Aluminum metal matrix composite welds have been produced by non-transferred plasma arc spraying of aluminum alloy powder containing SiC (Osprey powder). Almost no Al₄C₃ phase was observed in the sprayed deposit. However, the deposit contained excess soluble silicon because of pyrolysis of some SiC particulates. Heat treatment after spraying tends to improve the strength significantly, possibly by enhancing the bond between the substrate and the deposit and/or by improving the bonding between the particulates and the aluminum matrix, as well as by improving the deposit matrix itself. Hot isostatic pressing of the samples to eliminate porosity had only a small effect on the final strength of the joint.