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采用熔融玻璃净化技术研究了三元Fe_(35)Cu_(35)Si_(30)合金的液相分离与枝晶生长特征。实验获得的最大过冷度为328 K(0.24T L)。结果表明,合金在深过冷条件下具有三重凝固机制。当过冷度小于24 K时,α-Fe相为初生相,凝固组织为均匀分布的枝晶。过冷度超过24 K之后,合金熔体分离为富Fe区和富Cu区。在过冷度低于230K的范围内,Fe Si金属间化合物为富Fe区的初生相;当过冷度高于230 K时,Fe_5Si_3金属间化合物取代Fe Si相成为富Fe区的初生相。随着合金过冷度的增加,Fe Si相的生长速率逐渐升高,而Fe_5Si_3相的生长速率将逐渐降低。在富Cu区,初生相始终为Fe Si金属间化合物。能谱分析表明,富Fe区和富Cu区的平均成分均已严重偏离初始合金成分。
The characteristics of liquid phase separation and dendritic growth of ternary Fe_ (35) Cu_ (35) Si_ (30) alloys were studied by using the purification technology of molten glass. The maximum degree of undercooling experimentally obtained was 328 K (0.24 T L). The results show that the alloy has a triple solidification mechanism under deep subcooling conditions. When the degree of undercooling is less than 24 K, the α-Fe phase is the primary phase and the solidified structure is uniformly distributed dendrites. After the undercooling exceeds 24 K, the alloy melt separates into Fe-rich zone and Cu-rich zone. In the range of undercooling below 230K, the FeSi intermetallics are the primary phase of the Fe-rich zone. When the undercooling is higher than 230K, the Fe-5Si3 intermetallic compound replaces the FeSi phase and becomes the primary phase of the Fe-rich zone. With the increase of undercooling, the growth rate of Fe Si phase gradually increases, while the growth rate of Fe 5 Si 3 phase decreases gradually. In the Cu-rich region, the primary phase is always FeSi intermetallics. EDS analysis showed that the average composition of the Fe-rich and Cu-rich areas has deviated significantly from the initial alloy composition.