Compression Isentropes of Aluminum and Copper up to 200 GPa

The equation of compression isentropes derived from linear and quadratic Hugoniot curves has been obtained by employing the Hugoniot as the reference of Grneisen EOS as well as from p=f(e,v) form EOS directly. The compression isentropes of aluminum and copper are calculated with both Grneisen and Appy EOS. The calculated results show that the compression isentrope of aluminum under 200 GPa calculated with Appy EOS approaches to that with the linear Hugoniot, where the error is less than 1.5%. It is also compared with the ICE data of Shot Z864 at the Sandia Z machine. They agree very well under 200 GPa and derived from both the linear Hugoniot and the Appy EOS, for those where the error is less than 1%. The isentropes of aluminum derived directly from Appy EOS coincides almost with the experimental one.