金属银在高升温速率下的熔化和过热行为

Melting and Superheating of Ag at High Heating Rate

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的熔化和过热行为的影响.模拟中考虑了缺陷和表面对熔化和过热行为的影响.研究结果表明,升温速率对金属银的熔化和过热行为有很大影响,随着升温速率的升高,金属银的熔点有所升高.高的升温速率会导致金属银体系内部无序化程度增加,降低了熔化相变的能垒.升温速率导致的银完美晶体的过热极限大约为1450K.

Molecular dynamics simulations are employed here to study the behaviors of bulk Ag superheating and melting at high heating rate. The superheating and melting behavior are found to be strongly affected by the heating rate. The larger the heating rate, the higher the melting temperature, and there is an upper limit for the heating rate induced superheating. Stability study shows that the radomization induced by high heating rate is the main reason for the reduction of the energy barrier on phase transformation and for the existence of dynamic limit of superheating. Both Ag crystals and Ag crystals with defects are studied. The upper limit of heating rate induced superheating of perfect Ag crystal is determined to be around 1450 K.