高硼低碳铁基合金凝固组织研究

Study of solidification structure of Fe-B-C cast alloy

借助光学显微镜、扫描电镜、电子探针显微分析仪和X衍射分析等手段,研究了B含量>1wt%和C含量<0.2wt%的Fe-B-C铸造合金的凝固组织及合金元素的分布特征。研究发现,Fe-B-C铸造合金的凝固组织由硼化物、铁素体和珠光体组成,而且硼化物全部是Fe2B,显微硬度达到1430-1480HV,硼化物沿晶界呈网状分布。随着凝固冷却速度增加,凝固组织和硼化物明显细化。研究还发现,快速冷却条件下,硼化物数量减少,铁素体有增加趋势。另外,硼主要分布在硼化物中,基体中分布甚微。

The solidification structures of cast Fe-B-C alloy containing more than 1% B and lower than 0.2% C and the distribution characteristics of alloy elements were investigated by means of optical microscopy (DM), scanning electron microscopy (SEM), electron probe microanalyzer (EPMA) and X-ray diffraction (XRD). The results show that the solidification structures of cast Fe-B-C alloy consist of pearlite, ferrite and boride (Fe2B) with hardness of 1430-1480 HV. Boride distributes along grain boundary in the network form. Solidification structures and boride refine obviously with the increase of solidification cooling speed. In the condition of fast cooling, the amount of boride in Fe-B-C alloy decreases and the amount of ferrite increases. Moreover, boron element mainly distributes in the boride and there is little distribution in the matrix.