稀土镁变质处理对高硼铁基合金组织和性能的影响

Effect of Complex Modification of RE -Mg on Structure and Mechanical Properties of High Boron Iron-Based Alloys

为提高高硼铁基合金的性能,研究了两种变质处理方法对Fe-0.45C-1.5B高硼铁基合金的凝固组织与性能的影响。结果表明:高硼铁基合金的组织主要由铁素体、少量马氏体以及硼碳化合物组成,硼碳化合物呈网状沿晶界分布。经稀土镁合金变质后的基体组织较稀土硅铁合金变质后更加细化,且共晶组织中层片状硼碳化合物变短、变细,出现了多处明显颈缩和断网现象,导致部分硼碳化合物的团球化。经稀土镁合金变质处理后材料的硬度提高,冲击韧度和耐磨性能明显提高。

Two modification methods on solidification microstructure and properties of Fe-0.45C-1.5B were studied. The results show that high boron iron-based alloy is mainly composed of ferrite, a small amount of martensite and borocarbide that distribute reticularly along the grain boundaries. After RE-Mg modification, its matrix is obviously more refined than RE-Si modification, lamellar carbon-boron compounds become shorter and thinner in the eutectic microstructure, and necking and broken net appear in many positions, which results in spheroidization of the part borocarbide compounds. The hardness of high boron iron-based alloy increased after RE-Mg modification, and the impact toughness and wear resistance were significantly improved.