电弧熔炼Cr-Nb合金中晕圈的形成机制
Halo formation in arc-melted Cr-Nb alloys
本文采用真空非自耗电弧熔炼法制备了Cr-12%Nb和Cr-20%Nb 两种成分合金的纽扣锭，并对其凝固组织进行了研究。研究发现，亚共晶Cr-12%Nb合金在冷却速率相对较低的位置形成了晕圈，这些晕圈体现为非小平面的初生Cr相外面包裹着一层小平面的Cr2Nb相，过共晶Cr-20%Nb合金的凝固组织中没有发现晕圈。本文基于TMK快速共晶生长模型和BCT快速枝晶生长模型，计算得到了快速凝固条件下Cr-Cr2Nb合金系的共生区，计算结果表明，Cr-12%Nb合金的液相延长线处于共生区内，而Cr-20%Nb合金的液相延长线则处于共生区之外，说明电弧熔炼Cr-12%Nb合金中晕圈的形成除了受共生区形状及位置的影响外，还受共晶领先相Cr2Nb形核能力的影响。
Microstructures of two Laves phase Cr2Nb alloys with nominal compositions of Cr-12%Nb and Cr-20%Nb prepared by vacuum non-consumable arc-melting were investigated. For the Cr-12%Nb hypoeutectic alloy, halos of Cr2Nb Laves phase around the primary Cr dendrites were observed in the positions that experienced relatively low cooling rates. However, no halo occurred in the arc-melted Cr-20%Nb hypereutectic alloy. Simultaneously, the coupled zone of Cr-Cr2Nb system was calculated using the TMK model and BCT dendritic growth model. The calculated results indicate that the liquidus extension of the Cr-12%Nb alloy fall within the coupled zone, while for the Cr-12%Nb alloy, its liquidus extension is out of the coupled zone. Consequently, the formation of halo structure in the arc-melted Cr-12%Nb alloy is not only affected by the shape and position of the coupled zone, but also influenced by the solidification behavior of the leading phase Cr2Nb.
李克伟、傅恒志、李双明
有色金属冶炼
电弧熔炼离异共晶晕圈Laves相Cr2Nb
arc-meltingdivorced eutectichaloLaves phase Cr2Nb
李克伟,傅恒志,李双明.电弧熔炼Cr-Nb合金中晕圈的形成机制[EB/OL].(2011-11-17)[2025-08-11].http://www.paper.edu.cn/releasepaper/content/201111-287.点此复制
评论