Application of small specimen testing technique for mechanical property assessment of discontinuously reinforced composites

Abstract

The shear punch experiment is a small specimen testing technique that has been used to assess the flow properties, such as strength and ductility, of traditional engineering alloys when material availability is limited. In the present study, the applicability of a laboratory shear punch testing system, which was fabricated to evaluate the mechanical properties of different materials (steels, aluminium alloys, copper alloys, titanium alloys and cobalt alloys), was extended to include tensile mechanical property assessment of discontinuously reinforced metal matrix composites. In employing this testing technique to discontinuously reinforced composites, the shear punch load–displacement data were examined to identify the critical regions of the flow curve, i.e. elasticity followed by yielding, work hardening, ultimate tensile strength and fracture. The load–displacement curves and the fracture characteristics generated by shear punch testing were then compared with the conventional tensile data and failure behaviour in order to calibrate the method for composite materials. It was determined that the flow characteristics from shear punch testing can be used to predict the mechanical properties of discontinuously reinforced metal matrix composites through linear correlations for the yield strength, ultimate tensile strength and percent elongation.