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采用超高真空落管无容器处理技术研究了Fe-19.1%Si-7.8%Ti三元共晶合金的快速凝固。理论计算表明,在自由落体条件下Fe-19.1%Si-7.8%Ti三元共晶合金获得的过冷度范围为:37~259K;冷却速率范围为:4.81×103~2.48×105K/s。由XRD和EDS点分析结果得出,在较小过冷度下,合金的凝固组织由(Fe3Si+Fe5Si3)二相共晶和(Fe2Si+τ3)二相层片共晶构成,生成(Fe2Si+τ3)二相层片共晶的原因可能是发生了Fe3Si+Fe5Si3→Fe2Si+τ3固态相变;在大过冷度下,(Fe2Si+τ3)二相层片共晶消失,固态相变被抑制。
The rapid solidification of Fe-19.1% Si-7.8% Ti ternary eutectic alloy was investigated by using an ultra-high vacuum drop tubeless vessel processing technology. Theoretical calculations show that the range of undercooling obtained from Fe-19.1% Si-7.8% Ti ternary eutectic alloy is from 37 to 259 K and the cooling rate ranges from 4.81 × 10 3 to 2.48 × 10 5 K / s under free-fall conditions. The results of XRD and EDS analysis show that the solidification microstructure of the alloy is composed of (Fe3Si + Fe5Si3) two phase eutectic and (Fe2Si + τ3) two phase eutectic under the condition of low supercooling to form (Fe2Si + τ3) The eutectic of the two-phase lamellae may be due to the solid state transformation of Fe3Si + Fe5Si3 → Fe2Si + τ3. Under the condition of high undercooling, the eutectic of (Fe2Si + τ3) .