Multi-step Kolsky bar loading of materials which fail by adiabatic shear banding

Abstract

In a previous work we showed that thermal softening of materials, in Kolsky bar tests, can be eliminated by multiple-step loading. In this paper we present results from multi-step loading tests performed in our interferometry-based Kolsky bar, with specimens made of different alloys in order to further explore the nature of adiabatic shear failure. Particularly, we are interested in reducing the inherent temperature rise of the deformed specimens, in order to highlight the propensity of these alloys to the shear-banding failure. The multi-step loading should prevent the local heating of the specimen and may move the occurrence of shear banding to higher strains. Our experiments showed that specimens which fail at low strains have the same failure strains under multi-step and single loadings. On the other hand, specimens which failed at high strains, under a single loading, show a significant increase in their failure strain under the multiple-step loading. © Published under licence by IOP Publishing Ltd.