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通过对试样进行深度腐蚀,利用扫描电镜研究不同碳含量的V9Cr5Mo2高速钢中碳化物的三维形貌,并进一步讨论了碳化物的形态与合金凝固结晶过程的关系。结果表明,V9Cr5Mo2高速钢中碳化物主要由VC及以铬、钼为主的复合碳化物组成;共晶VC为枝晶状,先析出VC为不规则块状、开花状、卵石堆积状及团球状;以铬为主的复合碳化物为曲面板条状;富钼复合碳化物为鱼骨状。合金中含碳量1.6%时,碳化钒主要为共晶VC;碳含量为2.5%时,VC主要为大量共晶VC及部分不规则团块状、开花状的初生VC;碳含量为3.2%及4.2%时,VC为大量初生VC。随着含碳量的增加,VC的形态也由卵石堆积状向分散分布的团球状转变。
The three-dimensional morphology of carbides in V9Cr5Mo2 high-speed steel with different carbon contents was studied by scanning electron microscope (SEM). The relationship between carbide morphology and solidification and crystallization process was also discussed. The results show that the carbides in V9Cr5Mo2 high-speed steel are mainly composed of VC and complex carbides mainly composed of chromium and molybdenum; the eutectic VC is dendritic, the first precipitated VC is irregular lumps, flowering, pebbles accumulation and group Spherical; chromium-based compound carbide curved surface strip; rich molybdenum composite carbide fishbone. When the content of carbon in alloy is 1.6%, the vanadium carbide is mainly eutectic VC. When the content of carbon is 2.5%, VC is mainly composed of a large amount of eutectic VCs and some irregularly aggregated and flowering primary VCs. The carbon content is 3.2% And 4.2%, VC is a large number of newborn VCs. With the increase of carbon content, the morphology of VC also changes from pebbles to scattered clusters.