升温速率对金属熔化和过热的影响

采用分子动力学方法和QSC(QuantumSutton Chen)力场研究了升温速率对金属银和金属铅的熔化和过热行为的影响。研究结果表明,升温速率对金属银和铅的熔化和过热行为有很大影响,随着升温速率的升高,金属的熔点有所升高。高的升温速率会导致金属体系内部无序化程度增加,降低了熔化相变的能垒。升温速率导致的银和铅完美晶体的过热极限分别为1450K和800K。

Ag melting and superheating at high heating rate

Molecular dynamics simulation and QSC field are employed to study bulk Ag and Pb superheating and melting behaviors at high heating rate. It reveals that the superheating and melting behavior are strongly affected by the heating rate; the larger the heating rate, the higher the melting temperature. There is an upper limit of heating rate for the induced superheating. The heating rate induced randomization is the main reason to eliminate the energy barrier for phase transformation ocurring at high heating rate and it accounts for the existence of dynamic limit of superheating. The upper limit of heating rate induced superheating of perfect Ag crystal is determined to be around 1?450?K and that of perfect Pb crystal is 800?K.