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在大气中,采用熔融玻璃净化与循环过热相结合的方法,使Fe_(82)B_(17)Si_1共晶合金获得了342K(0.238T_E,T_E为共晶温度)的大过冷度。对该合金的冷却再辉曲线及凝固组织研究发现:(1)在6～164K及255～342K过冷度范围内该合金的冷却曲线仅呈现一次再辉,而在174～247K过冷度范围内其冷却曲线则存在两次再辉,三过冷度范围内的凝固组织分别对应于由准规则共晶和复杂规则共晶组成的混合共晶或混合共晶+非规则共晶、完全非规则共晶、初生α(Fe,Si)相+枝晶间非规则共晶;(2)在过冷条件下,该合金的共晶两相α(Pe,Si)及Fe_2B相满足促发形核的非互惠原则;(3)该合金非规则共晶出现的特征过冷度ΔT_1=63K,完全非规则共晶化的特征过冷度ΔT_2=164K;(4)该合金非平衡状态下的共晶共生区偏向Fe_2B相一边,它与共晶成分线的交点在ΔT=154K及ΔT=264K,其谷值约在ΔT=207K左右。
In the atmosphere, the combination of glass melting and overheating was used to obtain a large undercooling of 342K (0.238T_E, T_E is the eutectic temperature) for the Fe_ (82) B_ (17) Si_1 eutectic alloy. The cooling recrystallization curve and the solidification microstructure of the alloy were studied. The results showed that: (1) The cooling curve of the alloy showed only one reflow within 6 ~ 164K and 255 ~ 342K subcooling range, while in the range of 174 ~ 247K subcooling The cooling curve in the cooling curve exists twice, and the solidified structures in the three degrees of undercooling correspond to the mixed eutectic or mixed eutectic + irregular eutectic composed of quasi-regular eutectic and complex regular eutectic, respectively Regular eutectic, and irregular (α, Fe) phase and interdendritic eutectic between primary α (Fe, Si) phase and dendrites. (2) Under supercooled condition, the eutectic two phase α Nuclear non-reciprocal principle; (3) the characteristic undercooling ΔT_1 = 63K of the alloy irregular eutectic and the characteristic undercooling ΔT_2 of completely irregular eutectic ΔT_2 = 164K; (4) The eutectic zone is located on the side of Fe 2 B phase. The intersection point with eutectic composition line is at ΔT = 154K and ΔT = 264K, and its valley value is about ΔT = 207K.