Confirmation of machine-induced load oscillations during superplastic tensile testing

Abstract

The mechanical characterization of superplastic materials plays an important role in aiding the understanding of deformation mechanisms as well as in establishing properties critical to developing forming parameters for the fabrication of components. The flow stress of such materials is a strong function of strain rate and temperature, and it is generally found that strain hardening occurs as well. However, in the measurement of the flow stress, it is often found that rapidly oscillating loads occur during straining. Such load oscillations can have important implications in the identification of deformation mechanisms, if such oscillations are caused by the deforming material, and are otherwise important in establishing test procedures and test equipment if related to the these.