Abstract
A series of plate impact experiments have been performed on the three principal orientations of single crystal aluminium: [100], [110] and [111]. Experiments were designed to probe the Hugoniot Elastic Limit, spall strength and Equation of state as well as understand the microstructural response, via transmission electron microscopy, Transmission Kikuchi Diffraction and mechanical testing of shocked material. Results from this work, show that orientation affects the HEL and spall strength in a similar manner to the quasi-static uniaxial stress compressive response, with [100] and [110] being similar and [111] significantly stronger. This correlates with expectations from considerations using the Schmid analysis. However we have noted that similar studies in copper yield a different ordering of the HELs. We have reconciled those differences using an analysis based on second order elastic constants. However the shocked microstructures and post shock quasi-static mechanical response are strongly influenced by orientation. The [100] orientation shows a response typical of high stacking fault face centred cubic metals, consisting of equiaxed subgrains and a strong post shock hardening during quasi-static mechanical testing, similar to results in polycrystalline aluminium. In contrast, the [110] and [111] orientations have a microstructural response more similar to polycrystalline aluminium after repeated shock loading excursions, combined with much lower post shock hardening during mechanical testing. This suggests that these orientations require much greater dislocation activity to achieve the same plastic deformation as [100]. This would appear to agree with the much higher degree of work hardening observed in these orientations compared to [100].
| Original language | English |
|---|---|
| Article number | 118727 |
| Journal | Acta Materialia |
| Volume | 246 |
| DOIs | |
| State | Published - Mar 1 2023 |
| Externally published | Yes |
Funding
This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001 ). We would like to thank Dave Chapman and Steve Johnson from Imperial College London for performing the first series of shots in this report. We are also grateful to X. Yan, S. Pickering, S. Doak and G. West from the University of Loughborough for performing the EBSD anaylsis on the single crystals. Finally, we would like to acknowledge Carl Trujillo for performing the gas-gun shots at LANL. UK Ministry of Defence© Crown Owned Copyright 2020/AWE. Published with permission of the Controller of Her Britannic Majesty's Stationary Office. “This document is of United Kingdom origin and contains proprietry information which is the property of the Secretary of State for Defence. It is furnished in confidence and may not be copied, used or disclosed in whole or in part without prior written consent of Defence Intellectual Property Rights DGDCDIPR-PL – Ministry of Defence, Abbey Wood, Bristol, BS34 8JH, England”, This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001).
Keywords
- Aluminium
- Microstructure
- Orientation
- Shock loading
- Single crystal