中文摘要：

为了研究液态镓结构变化的滞后性,采用基于四电极法的电阻动态测量系统,对过热和过冷液态镓在加热、冷却和保温过程中其电阻率的变化规律进行了动态测定.结果发现液态镓的电阻率随熔体快速加热后保温时间的延长而增大、随熔体快速冷却后保温时间的延长而减小.慢速升温熔体的电阻率明显大于快速升温熔体在同一温度下的电阻率,其影响只在熔体升温速度小于0.13℃/min时才能显现出来.液态镓从过热状态降温到过冷状态后,其电阻率-温度曲线保持了很好的连续性.但其在过冷状态下的变化规律与未过热熔体的明显不同.从液态镓电阻率实验结果可以推出,液态镓的结构随温度的变化存在滞后性.当升温速度大于0.13℃/min时,液态镓的结构随温度的变化具有完全滞后的特点.

英文摘要：

By using a dynamic test system based on four-point probe method for measuring resistance m order to study the hysteresis of melt structure variation of liquid gallium, the resistivities of liquid gallium superheated and undercooled during heating process, cooling process and holding process have been measured. It is found that the resistivity of liquid gallium increases with increasing the holding time after a rapid heating process, and decreases after a rapid cooling process. At the same temperature, the resistivity of liquid gallium heated at a lower heating rate is larger evidently than that at a higher heating rate. However, the effect of the heating rate on the resistivity is evident only when the heating rate is lower than 0. 13 ℃/min. The resistivity-temperature curve of liquid gallium is continuous when the superheated liquid gallium is cooled below the melting point. But it is different evidently from the resistivity-temperature curve of the non-superheated liquid gallium. From result of resistivity, it can be deduced that the structure variation of liquid metal after a temperature variation process exists hysteresis. And the hysteresis of the structure variation of liquid gallium is complete when the heating rate is higher than 0. 13 ℃/min.