On the microstructure, mechanical behaviour and damping characteristics of Al–Zn based composites reinforced with martensitic stainless steel (410L) and silicon carbide particulates

Abstract

The microstructural characteristics, mechanical and damping properties of Al–Zn based composites reinforced with 6, 8, and 10 wt% martensitic stainless steel (SS) and 10 wt% silicon carbide (SiC) were investigated. The composites were produced via double stir casting process, and structural assessment was undertaken with the use of scanning electron microscopy (SEM) and X-ray diffraction analysis. The mechanical properties (hardness and tensile properties) and damping behaviour were also evaluated. The microstructures showed well delineated particles varied particle size and dispersion patterns, while the XRD results indicated marginal presence of reaction induced intermetallic phases. Relative to the unreinforced Al–Zn alloy, the hardness, ultimate tensile strength (UTS), specific strength improved with increase in SS wt. % (18%, 26%, 44% for hardness; 33%, 40%, 51% for UTS; and 19%, 28%, 47% for specific strength, for 6, 8, and 10 wt% SS particles, respectively). Also, all the Al–Zn/SS composite grades had strength and ductility characteristics superior to that of the Al–Zn/SiC composite. Particle and interface strengthening, was linked to the improved strength offered by these grades of composites, while more uniform strain distribution due to the inherent ductile and deformable nature of the SS particles, attested to by the relatively higher signs of dimple fractures; was linked to the superior ductility. The damping capacities of all the Al–Zn based composites were higher than that of the unreinforced Al–Zn alloy, with the inherent damping capacities of constituents, constituent weight proportions, particle/interface mobility sensitivity to temperature, and dislocation damping effects, linked to the variations in damping behaviour exhibited by the Al–Zn based composites.