中文摘要：

为了探讨液-液结构转变的可逆性及熔体状态对凝固的影响,利用直流四电极法测量SnSb15合金熔体在三轮连续升降温过程中的电阻率-温度曲线。分析SnSb15合金熔体的不可逆和可逆转变的物理内涵,进而讨论不可逆转变对凝固影响的作用机制。结果表明：SnSb15合金熔体发生了温度诱导的液-液结构转变,其首轮升温过程的转变呈不可逆性,而后续降温及升温过程的转变呈可逆特征;且首轮升温过程的不可逆液-液结构转变显著影响合金的凝固行为和组织,如初生相和包晶相的形核过冷度分别增大9.7和5℃,凝固时间分别缩短2.5和4 s,并且凝固组织明显细化。

英文摘要：

In order to study the reversibility of liquid-liquid structure transition（L-LST） and the effects of melt state on solidification,the electrical resistivity-temperature curves of SnSb15 melt were measured in three heating and cooling cycles by means of DC four-probe method.The physical connotation of irreversible and reversible L-LST was analyzed,and the effects of irreversible L-LST on solidification were also discussed.The results show temperature induced L-LST occurs in SnSb15 melt.L-LST in first heating process is irreversible,but it is reversible in subsequent cooling and heating processes.Besides,irreversible L-LST can significantly affect the solidification behavior and microstructure,i.e.the undercooling degrees for primary and peritectic phase enlarge 9.7 and 5 ℃,the solidification time shortens 2.5 and 4 s,respectively.Moreover,the solidification microstructures are refined obviously.