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液态Fe-10%Sb合金在熔融玻璃净化和自由落体实验条件下,分别达到429K(0.24TL)和568K(0.32TL)过冷度.深过冷并没有改变合金的相组成,快速凝固组织中只有αFe单相固溶体.熔融玻璃净化实验研究发现,αFe枝晶生长速度随过冷度呈指数函数变化.当过冷度?T<296K时,枝晶生长速度随过冷度增大而升高,并在296K过冷度处达到极大值1.38m/s.若合金过冷度进一步增大,αFe枝晶生长速度则呈现降低趋势.枝晶生长形态演变的主要规律是,小过冷条件下αFe相以粗大枝晶方式生长,而深过冷合金熔体中形成蠕虫状枝晶.溶质截留程度主要取决于实际枝晶生长速度而不是过冷度大小,同时也与冷却速率相关.由于其结晶温度间隔比较宽大,尽管快速枝晶生长显著抑制了溶质偏析,但是Fe-10%Sb合金仍难以实现完全无偏析凝固.
The liquid Fe-10% Sb alloy reached the undercooling of 429K (0.24TL) and 568K (0.32TL) under the condition of purifying and free-fall glass melt respectively.The deepcooling did not change the phase composition of the alloy, Only αFe single phase solid solution.Experimental study of molten glass purification found that the growth rate of αFe dendrite changes exponentially with undercooling degree.When the degree of undercooling is less than 296K, the dendrite growth rate increases with the increase of undercooling , And reached a maximum of 1.38m / s at a subcooling degree of 296 K. If the undercooling of the alloy further increases, the growth rate of αFe dendrites shows a decreasing trend.The main rule of dendrite growth morphology evolution is that the supercooling conditions The lower αFe phase grows in the form of coarse dendrites, whereas the worm-like dendrite forms in the deep undercooled melt.The degree of solute rejection mainly depends on the actual dendritic growth rate rather than the degree of subcooling, and also on the cooling rate. The crystallization temperature interval is relatively wide. Although rapid dendrite growth significantly inhibits solute segregation, Fe-10% Sb alloy is still difficult to achieve complete segregation-free solidification.