Planar shock compression of single crystal tantalum from 6 _ 23 GPa

18th APS-SCCM; 24th AIRAPT

Whiteman, G.^1 ; Case, S.^1 ; Millett, J.C.F.^1

AWE, Aldermaston, Reading, Berkshire

RG7 4PR, United Kingdom^1

关键词: Dislocation densities;    Dislocation motion;    Impact experiment;    Polycrystalline;    Principal orientations;    Single crystal plasticity;    Thermally activated;    [100] orientation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/11/112067/pdf
DOI  :  10.1088/1742-6596/500/11/112067

来源: IOP

【 摘 要 】

Planar impact experiments have been performed to produce simultaneous shock loading of the three principal orientations of single crystal tantalum ([100], [110] and [111]) to peak stresses of 6 and 23 GPa. Results reveal that the [100] orientation exhibits the largest elastic limit. Shock velocity measurements indicate that for all of the materials, and most notably in the [100] orientation, there is a low stress excursion from a linear Us-upplot similar to that previously seen in polycrystalline tantalum. This suggests sensitivities at low stress which require further investigation. The experiments have been simulated using a single crystal plasticity finite element model that accounts for thermally-activated and drag-resisted dislocation motion, and for evolution of the dislocation density. The model is seen to qualitatively describe some of the features described above.