A rapid drop of pressure applied to a melt whose crystallization point is a decreasing function of the pressure may,if the temperature,the initial pressure and the final pressure are appropriately chosen,be equivalent to a rapid thermal quenching.In particular,it may lead to the formation of metastable crystalline or glassy-phase bulk materials.The method might be useful to simulate adiabatic decompressions subsequent to shocks,such as meteorite impacts.The relation between the corresponding cooling rate(Vc) obtained by rapid decompression and the rate of pressure release(Vp) is first given by Vc=KVp,where K is the drop rate of melting point with pressure.This method is evaluated by using Al-Ge system.Our experimental results indicate that quenching with rapid decompression is an effective method for generating corresponding high cooling rate of more than 105K·s-1.