Study on the release process of $\gamma $ and $\alpha $ phase transition in cerium material

Cerium has lots of phase transition in high pressure and temperature. A volume change of about 15{\%} occurs when Cerium is subject to high pressure ($\sim $0.7GPa) and $\gamma \to \alpha $ phase change takes place. The phase transition and constitutive model of Cerium can be respectively obtained by calculating the experiment results and taking account of the multi-phase equation of state (EOS). The calculated results indicate that in loading condition the phase transition pressure of Cerium is higher than quasi-static compression. The calculated results indicate that the phase transition under release is difficultly described because the $\alpha \to \gamma $ phase reversal is great influenced by plastic flow. Based on multi-phase equation of state, constitutive model and non-equilibrium phase transition equation, introducing quasi-elastic unloading rule simulated the phase transition under release. The calculated result is according with the experiment.