CONTRASTING THE DIFFERENCES IN THE SHOCK RESPONSE OF FACE CENTRED CUBIC AND BODY CENTRED CUBIC METALS

To gain a greater understanding of the response of materials to shock (or any other mode of loading) it is often beneficial to start from a simple, well controlled state. In this case, this will be in single, chemically pure crystals with known loading orientations, namely (100), (110) and (111). The materials chosen are typical of FCC and BCC metals; respectively aluminium and tantalum. In this presentation, we will examine how orientation effects deformation, both from mechanical (Hugoniot Elastic Limit) and microstructural development standpoints. We will look at how a simple elastic analysis based on second order elastic constants can be used to determine the ratio of HELs as a function of orientation in FCC metals, even when the ordering appears to disagree with predictions made using the Schmid analysis, and how in BCC metals this analysis requires modification to take into account non-Schmid behaviour. Microstructural and mechanical analysis of recovered samples after shock loading show how changing the loading orientation of the signle crystal can have a major effect on microstructural development and post shock mechanical properties such as shock hardening and work hardening. UK Ministry of Defence © Crown Owned Copyright 2023/AWE.