Shock-induced volume-collapse phase transition in a Ce-La alloy dynamically compressed up to 20 GPa

Understanding the complex multiphase properties of Ce and its alloys remains a long-standing scientific challenge. Here, we report experimental observations of the shock responses of Ce-5wt. %La alloy dynamically compressed up to 20 GPa using plate-impact shock experiments. The Ce-5wt. %La alloy is observed to undergo a volume collapse phase transition (PT) from the $\ensuremath{\gamma}$ to the $\ensuremath{\alpha}$ phase with a volume change of $\ensuremath{\sim}20%$ and the shock-compression PT region is found to be between 0.997 and 4.835 GPa. Thermodynamic analysis shows that the few La additives markedly elevate the PT threshold pressure of Ce. The obtained experimental $P\ensuremath{-}V$ and ${u}_{s}\ensuremath{-}{u}_{p}$ results confirm the validity of the law of additive volumes for ideal mixtures for Ce-5wt. %La in an experimental pressure range from the $\ensuremath{\alpha}$ phase to the liquid phase. These data and observations can provide a better understanding of the multiphase properties of dynamically compressed Ce and its alloys, and have potential industrial applications in the synthesis of new materials at high pressures.