An experimental investigation of effects of specimen size parameters on compressive and tensile properties in a closed cell Al foam

Abstract

Effects of specimen size parameters, i.e. the specimen volume and the ratio of cross sectional dimension to cell size, on compressive and tensile properties were investigated in a closed cell Al foam. For compressive tests, the stress in a plateau region decreased with decreasing specimen volume. This is likely because constraint of cell walls at the free surface is reduced with decreasing specimen volume. The scatter of the stress was large for the small volume specimens. The critical ratio of cross sectional dimension to cell size was 4 for negligible scatter of the stress. For tensile tests, the ultimate tensile strength decreased, the elongation to failure increased and the work hardening coefficient decreased with decreasing specimen volume. It is suggested that the reduced constraint of cell walls at the free surface by decreasing specimen volume affects the tensile strength as well as the compressive strength.