Sn-70Bi合金熔体结构转变的可逆性及其凝固行为

Reversibility of the Liquid-liquid Structure Transition in Sn-70Bi Alloy and its Solidification Behavior

利用直流四电极法研究了Sn-70Bi合金在液相线以上数百度温度范围内发生的熔体结构转变;在此基础上,进一步探讨了熔体结构转变的可逆性及其对凝固的影响。试验结果表明,Sn-70Bi合金所发生的熔体结构转变部分可逆,分析认为主要与Sn的熔体结构有关,且熔体结构转变对其凝固行为及组织有较大的影响。发现结构变化后的熔体凝固过冷度显著增大,初生相和共晶相组织明显细化。

The liquid-liquid structure transition of the Sn-70Bi alloy at more than liquidus in range of hundreds temperature has been investigated by direct current four-probe method.The reversibility of liquid-liquid structure transition and its influence on the solidification of Sn-70Bi alloy have been analyzed based on above mentioned result.It was found that the liquid-liquid structure transition of Sn-70Bi alloy exhibits partial reversibility,which is mainly related to the Sn molten structure,and the structure transition has obviously affect the solidification behavior and microstructure of the Sn-70Bi alloy.The under-cooling degree of the liquid-liquid structure transition melt can be greatly increased,which obviously refine the primary phase and eutectic phase.