Dynamic spallation processes of materials at high strain rates are of critical importance to a wide range of scientific and engineering disciplines, including astrophysics, material sciences, and aerospace engineering. It is involved in subjects like planetary collisions, jet engine debris impacts, and laser-driven impact experiments, etc. We show with molecular dynamics simulations that spinodal decomposition is a probable initiation mechanism of spallation in impact-melted samples at extremely high strain rates. The formation of voids or bubbles is a secondary process following the spinodal amplification of density fluctuations. As a result, the spallation strength can be related to the inherent thermodynamic property of the liquid, i.e., the liquid-gas spinodal curve, which can be determined by independent equation-of-state studies in prior. This connection between high strain rate spallation and spinodal decomposition may be further examined in future experiments

spall,shock impact,liquid metal,spinodal