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采用多元合金相场模型及耦合真实热力学参数,对Ni-Al-Nb三元单相合金在不同过冷度及不同成分条件下的枝晶生长形态转化及显微偏析进行了研究.结果表明:在成分相同改变过冷度以及过冷度相同改变Nb含量两种条件下,随着无量纲过冷度U(U=ΔT/ΔT0,其中ΔT为过冷度,ΔT0为结晶温度间隔)的增大,两种条件下均出现枝晶形态由典型枝晶形态向球状晶形态转化,而枝晶显微偏析程度在两种条件下均呈现为先增大后减小的规律.
The morphology and microscopic segregation of dendritic growth of Ni-Al-Nb single phase alloy under different undercooling and different compositions were studied by using the multi-alloy phase field model and the coupled real thermodynamic parameters.The results show that: With both the same change in undercooling and the same change in undercooling, as the dimensionless undercooling U (U = ΔT / ΔT0, where ΔT is subcooling, ΔT0 is the crystallization temperature interval) Large and under both conditions, the dendrite morphology changed from typical dendritic morphology to spherical crystal morphology, and the degree of micro-segregation of dendrites increased first and then decreased under both conditions.