No abstract

Dynamic ductile fracture has been studied through incipient spallation experiments on two grades of tantalum. A commercially pure Ta material incipiently spalled at 252 m/s, a highly pure Ta material incipiently spalled at 246 m/s, and a highly pure Ta material preshocked at 250 m/s and incipiently spalled at 246 m/s were used. Microstructural parameters of the fracture process such as porosity, void-size distributions, and void aspect ratios have been quantified using image analysis and optical profilometry techniques. The commercially pure Ta, the highly pure Ta preshocked prior to spall, and the annealed high-purity Ta exhibited 27, 16.6, and 5.5 pct porosity, respectively. The void-size distribution observed in all three tests was adequately represented by either a log-normal or a linear combination of a log-normal and a Weibull distribution function. At least 80 pct of the aspect ratios observed in all three tests were adequately represented by a gamma distribution function.

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No abstract

Dynamic ductile fracture has been studied through incipient spallation experiments on two grades of tantalum. A commercially pure Ta material incipiently spalled at 252 m/s, a highly pure Ta material incipiently spalled at 246 m/s, and a highly pure Ta material preshocked at 250 m/s and incipiently spalled at 246 m/s were used. Microstructural parameters of the fracture process such as porosity, void-size distributions, and void aspect ratios have been quantified using image analysis and optical profilometry techniques. The commercially pure Ta, the highly pure Ta preshocked prior to spall, and the annealed high-purity Ta exhibited 27, 16.6, and 5.5 pct porosity, respectively. The void-size distribution observed in all three tests was adequately represented by either a log-normal or a linear combination of a log-normal and a Weibull distribution function. At least 80 pct of the aspect ratios observed in all three tests were adequately represented by a gamma distribution function.