Shear Punch Test for Strength and Ductility Measurements of Metal Matrix Composites

In this work, the applicability of small scale shear punch testing for determining tensile mechanical property information of discontinuously reinforced metal matrix composites was evaluated in order to overcome the expense and difficulty of generating large specimen volumes from composite materials processed in the laboratory. The shear punch test is based on blanking a circular disk from a fixed sheet specimen. It is instrumented to provide punch load-displacement data, which can be converted to tensile yield stress, ultimate tensile strength, work hardening exponent and reduction in area at fracture. In the case of traditional engineering alloys, a close correlation between tensile shear punch data and tensile test data has been identified, thus permitting a means of evaluating the flow properties, when only a small amount of material is available. In employing shear punch testing for discontinuously reinforced composites, the punch load-displacement data must be examined to identify the critical regions of the flow curve, i.e. elasticity followed by yielding, work hardening, an ultimate tensile strength and fracture. The load displacement curves generated in shear are then compared to the conventional tensile curves in order to calibrate the former.