Microstructural Evaluation of Cold Spray Deposited WC with Subsequent Friction Stir Processing

Abstract

Friction Stir Processing (FSP) has been shown to improve the strength, ductility and toughness of both aluminium and steel materials through grain refinement and the even distribution of precipitates within the substrate matrix. This article presents the application of FSP of Cold Spray deposited Tungsten Carbide-Cobalt (WC-Co) of two distinct types, on a series of aluminium substrates. Microstructural investigations of FSP processed samples exhibit interaction between the deposited WC-Co particles and aluminium alloy and show the homogeneous dispersion of deposited particles through the metal matrix. Results show that the dispersion of these particles varies with powder type, FSP parameters and substrate characteristics. A parallel study focusing on the hardness of the FSP generated Metal Matrix Composite (MMC) further demonstrate the potential of combining Cold Spray and FSP technologies to tailor surface properties for specific applications.