Cold Sprayed Additive Manufacturing of SiC/Al Metal Matrix Composite: Synthesis, Microstructure, Heat Treatment and Tensile Properties

Abstract

In this study, cold spray technique was used as a solid-state additive manufacturing route to deposit a 5 mm thick SiC /Al metal matrix composite. Microstructure and tensile properties were analyzed via different heat treatment conditions (200 oC, 300 oC, 400 oC and 500 oC). Microstructure evolutions were characterized via scanning electron microscopy, X-ray diffraction (XRD) and energy-disperse X-ray spectroscopy (EDS), whilst mechanical properties were investigated via micro-tensile and hardness tests. It was established that the as-sprayed deposit fractured in a brittle manner and had appreciable tensile strength (85 MPa) mainly associated with intensive work hardening effect. At heat treatment conditions, tensile strength (104 MPa) and plasticity (1.5 %-5.2 %) were enhanced due to coarsening of pure Al splat through recrystallization-recovery-grain growth mechanisms. The splat size which controls strength changes from 30.9 ± 2.6 μm to 40.9 ± 4.8 μm, an appreciation of 32 % as heat treatment temperature increased. The main fracture mode at the heat treatment state was a ductile fracture. For plastically deformed splats, the flattening ratios (FR) revealed the top (1.5), middle (1.9) and near interfacial regions (2.2) due to peening effect of SiC particles. The Young moduli were in agreement with the experimental results.