Accessing Ultra-High Pressure, Quasi-Isentropic States of Matter.

Lorenz, K. T. ; Edwards, M. J. ; Glendinning, S. G. ; Ho, D. D. ; Jankowski, A. F. ; McNaney, J. ; Pollaine, S. M. ; Remington, B. A.

Technical Information Center Oak Ridge Tennessee

关键词: Isentropic processes;    Lasers;    Materials strength;    Metals;    Acceleration;   

RP-ID  :  DE2005313929

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

A new approach to the study of material strength of metals at extreme pressures has been developed on the Omega laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, inferred from VISAR measurements of velocity, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor (RT) unstable interfaces. This paper reports the first attempt to use this new laser-driven, quasi-isentropic technique for determining material strength in high-pressure solids. Modulated foils of Al-6061-T6 were accelerated and compressed to peak pressures of 200 kbar.