Influence of strain state in mechanical behaviour of aluminium alloys using the Small Punch Test

The Small Punch Test (SPT) basically consists of deforming a miniature specimen, whose edges are firmly gripped by a die, using a high strength punch. This test was developed in the eighties and has since been used successfully on numerous occasions in those cases where there is not sufficient material to carry out standard tests to obtain the mechanical properties of materials. In recent years, it has been used successfully to determine the yield strength evolution in any area of stamped aluminium alloy components. These stamped components are subject to different kinds of plastic deformation during the stamping process. The main objective of this paper is to analyze the influence that the type of deformation reached during the stamping process has on the mechanical behaviour of the material. Furthermore, for each kind of strain, the yield load in the SPT will be related to yield strength to provide a unique valid expression to evaluate the hardening of the material.