Pb-Sb30%液-液结构转变的不可逆性及其对凝固的影响

Irreversibility of the Liquid-Liquid Structure Transition and Its Effect on the Solidification of Pb-Sb30% Alloy

在前期研究发现一些二元合金在液相线上数百度温度范围内发生温度诱导液-液结构转变的基础上,进一步研究了Pb-Sb30%合金液-液结构转变的可逆性,结果表明,该合金熔体发生的结构转变是不可逆的;并探讨了液-液结构转变对其凝固行为及组织的影响,发现结构变化后的熔体凝固过冷度增大,初生相和共晶相组织明显细化,且维氏硬度值提高约30%。

In our former investigations, the temperature-induced liquid-liquid structural transition （TI-L-LST） was suggested to occur in some binary alloys, within a certain range of several hundred degrees above the liquidus. In the present paper, the reversibility of the L-LST in Pb-Sb30% alloy is further studied, and the results show that the structural transition is irreversible. Moreover, the L-LST had a visible effect on the solidification behaviors and morphologies of Pb-Sb30% alloy. Associated to the liquid structural transition, the super-cooling degree was increased, and the primary phase and eutectic phase became fine, and the Vickers hardness of the sample increased about 30%.