The defect evolution in 1-D shocked tantalum single crystals

Tantalum single crystals were impacted along [001], [011] and [111] using 1-D planar shock waves with pressures of 6.4 GPa, 15.4 GPa and 21.7 GPa. The defect structures generated have been characterised using scanning electron microscopy and transmission electron microscopy. Deformation twins were produced in the 15.4 GPa and 21.7 GPa shocked samples, but are not seen in the 6.4 GPa samples. The twinning types were found to be highly dependent on the orientation of the single crystals and to obey the Smith [18] model. The remaining shock-induced dislocation structure is largely random, presumably as a result of the release wave. The TEM observations also show evidence of surface relaxation.