Spall strength and ejecta production of gold under explosively driven shock wave compression

[摘要] Explosively driven shock wave experiments were conducted to characterize the spall strength and ejecta production of high-purity cast gold samples. The samples were from 0.75 to 1.84 mm thick and 30 mm in diameter. Peak stresses up to 44 GPa in gold were generated using PBX-9501 high explosive. Sample free surface and ejecta velocities were recorded using photonic Doppler velocimetry techniques. Lithium niobate pins were used to quantify the time dependence of the ejecta density and the total ejected mass. An optical framing camera for time-resolved imaging and a single-image x-ray radiograph were used for additional characterization. Free surface velocities exhibited a range of spall strengths from 1.7 to 2.4 GPa (mean: 2.0 ??0.3 GPa). The pullback signals were faint, minimal ringing was observed in the velocity records, and the spall layer continued to decelerate after first pull back. These results suggest finite tensile strength was present for some time after the initial void formation. Ejecta were observed for every sample with a roughened free surface, and the ejecta density increased with increased surface roughness, which was different in every experiment. The total ejected mass is consistent with the missing mass model.

[发布日期] 2013-12-16

[学科分类] 材料科学（综合）

[关键词] GOLD;PRESSURE RANGE GIGA PA;IMAGES;SURFACES;DENSITY;SHOCK WAVES;X RADIATION;MASS;VELOCITY;TENSILE PROPERTIES;TIME RESOLUTION;COMPRESSION;ROUGHNESS;TIME DEPENDENCE;EXPLOSIVES;SIGNALS;STRESSES;VOIDS ejecta;spall;shock wave compression;gold