一种新的快速凝固方法──快速卸压淬火

A NEW METHOD FOR RAPID SOLIDIFICATIONQUENCHING BY RAPID DECOMPRESSION

对于固化温度随压力升高而降低的熔体，在适当的初始温度和压力下快速卸压，将使熔体快速固化．给出了通过快速卸压而获得相应过冷速率的计算公式，并用ＡｌＧｅ系统对这种新的快速凝固方法进行了评估．实验结果表明用此种方法能获得大于１０５Ｋ·ｓ－１的过冷速率，因而有利于制备大块亚稳材料甚至非晶．同时，通过快速卸压而实现快速凝固的原理。

Abstract 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(Vc) obtained by rapid decompression and the rate of pressure release(Vp) is first given by Vc=KVp,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 105K·s-1.