Dynamically Determined Pressure-Volume Relationships for Aluminum, Copper, and Lead

Abstract

This work presents experimentally determined pressure-volume data for copper to 116 kbars, lead to 78 kbars, and 1060 aluminum to 39 kbars. At these low stresses, the shear strength cannot be ignored; therefore, the dynamic stress-strain curves are reduced to Hugoniot form for further correction to ``shock hydrostats.'' These data may be compared to either isothermal hydrostatic data or to ultrasonic and very high-pressure dynamic data. In the former, polynomial pressure-volume data fits are corrected thermodynamically to isothermal conditions through the Grüneisen equation of state. Copper and aluminum dynamic curves are in reasonable agreement with the Bridgman curves; lead, on the other hand, shows marked discrepancies. In the latter comparison, the pressure-volume data are reduced to a bulk shock velocity and particle velocity plot. These data fit smoothly with the very high dynamic pressure data. Copper gives a linear fit, aluminum a quadratic fit, and lead does not permit distinction between a linear or quadratic fit. Agreement between dynamic and ultrasonic data is extremely good and suggests high accuracy for the dynamic data.