A ductile iron casting containing Ni, Cr, W, Mo, and V was produced in the present study, and the decomposition of eutectic carbides at elevated temperature was systematically investigated. The as-cast sample mainly contained blocky eutectic (Fe, Cr)-rich M3C carbides, fishbone-shaped eutectic (W, Mo)-rich M6C carbides, and polygonal primary (V, W)-rich MC carbides. The Cr-rich M3C carbides were completely decomposed when exposing at 1050 ℃ for 7 h, during which carbon atoms mainly aggregated to form graphite because of the existence of Si and Ni. Part of the fishbone-shaped M6C carbides decomposed at 1050 ℃, and their morphology gradually evolved into fine rod-shape, followed by granular and nearly spherical shape with increasing holding time. The polygonal (V, W)-rich MC carbides changed little attributing to their high thermal stability.

中文翻译：

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新型Ni-Cr-W-Mo-V球墨铸铁的显微组织及其共晶碳化物的高温分解行为


本研究生产了含有 Ni、Cr、W、Mo 和 V 的球墨铸铁铸件，并系统研究了共晶碳化物在高温下的分解。铸态样品主要含有块状富共晶（Fe、Cr）M3C碳化物、鱼骨状富共晶（W、Mo）M6C碳化物和多边形初生富（V、W）MC碳化物。富Cr的M3C碳化物在1050 ℃下暴露7 h后完全分解，期间由于Si和Ni的存在，碳原子主要聚集形成石墨。部分鱼骨状M6C碳化物在1050 ℃分解，随着保温时间的延长，其形貌逐渐演化为细棒状，随后为粒状和近球形。富含多边形（V、W）的MC碳化物由于其高热稳定性而几乎没有变化。