Chin. Phys. B, 2008, Vol. 17(1): 264-269    DOI: 10.1088/1674-1056/17/1/046
 CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES Prev   Next

# Shear modulus of shock-compressed LY12 aluminium up to melting point

Yu Yu-Ying, Tan Hua, Hu Jian-Bo, Dai Cheng-Da
Laboratory for Shock Wave and Detonation Physics Research, Institute of\Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Abstract  Asymmetric plate impact experiments are conducted on LY12 aluminium alloy in a pressure range of 85--131\,GPa. The longitudinal sound speeds are obtained from the time-resolved particle speed profiles of the specimen measured with Velocity Interferometer System for Any Reflector (VISAR) technique, and they are shown to be good agreement with our previously reported data of this alloy in a pressure range of 20--70\,GPa, and also with those of 2024 aluminium reported by McQueen. Using all of the longitudinal speeds and the corresponding bulk speeds calculated from the Gruneisen equation of state (EOS), shear moduli of LY12 aluminium alloy are obtained. A comparison of the shear moduli in the solid phase region with those estimated from the Steinberg model demonstrate that the latter are systematically lower than the measurements. By re-analysing the pressure effect on the shear modulus, a modified equation is proposed, in which the pressure term of $P/\eta^{1/3}$ in the Steinberg model is replaced by a linear term. Good agreement between experiments and the modified equation is obtained, which implies that the shear modulus of LY12 aluminium varies linearly both with pressure and with temperature throughout the whole solid phase region. On the other hand, shear modulus of aluminium in a solid-liquid mixed phrase region decreases gradually and smoothly, a feature that is very different from the drastic dropping at the melting point under static conditions.
Keywords:  Steinberg model      shock compression      melting point      shear modulus      LY12 aluminium
Published:  20 January 2008
 PACS: 62.20.D- (Elasticity) 81.40.Jj (Elasticity and anelasticity, stress-strain relations) 64.30.-t (Equations of state of specific substances) 62.50.-p (High-pressure effects in solids and liquids)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos 10232040 and 10672149) and the foundation of Laboratory for Shock Wave and Detonation Physics Research, China Academy of Engineering Physics (Grant No 9140C6702020603).