高钒铁碳合金的凝固过程

Solidification Process of Fe-C Alloy Containing Rich Vanadium

通过定向凝固液淬实验、金相分析、电子探针面扫描、微区成分能谱分析和差热分析等手段,研究了高钒铁碳耐磨合金在稀土变质处理前后的凝固过程。结果表明:该合金在凝固时首先从液相中析出初生VC相,然后依次发生L→γ+MC和L→γ+MC+MC2的共晶反应。其中,MC是主要含钒的碳化物,MC2是主要含钼和铬的碳化物。初生VC在稀土变质处理前呈椭圆形、方形、菱形和多角形等形态,经稀土变质处理后,完全变成了球形。由于受多相共生生长方式的限制,共晶组织中的碳化物形态在变质处理前后没有明显变化。

By means of unidirectional solidification and quenching test, metallographic analysis, SEM energy spectrometry and DTA analysis, the solidification process of Fe-C alloy containing high vanadium was investigated. The results show that, during solidification, primary VC crystals precipitate from liquid firstly, and then the eutectic reactions are carried out as of L→γ+MC and L→γ+MC+MC_2. MC is the carbide containing V mainly, MC_2 containing Mo and Cr. Without modification, the primary VC crystals are formed in the shape of ellipse, square, rhombus and polygon. By modification with rare-earth, it becomes spherical. The morphology of carbide in eutectic structure is not influenced by modification almost.