原位合成核壳MC碳化物增强的M2高速钢

A modified M2 high-speed steel enhanced by in-situ synthesized core-shell MC carbides

采用高能湿球磨M2高速钢粉末和钒铁合金,通过真空烧结制备了原位合成核壳MC碳化物增强的M2高速钢。研究了球磨后复合粉末的相组成、形貌与成分分布,分析了烧结显微组织随温度的演变,以及测试了烧结样品热处理前后的力学性能。结果表明:球磨后的粉末完全细化成片状和团聚状,内部均匀分布着V元素。在1180℃下经过超固相液相烧结,改性的M2钢烧结体基本全致密化(~99.2%的相对密度)。近球形MC碳化物和不规则形状M_(6)C碳化物弥散分布在烧结高速钢的基体中,烧结液相的扩散与凝固促进MC碳化物形成了核壳结构。通过热处理,烧结合金的基体晶粒和碳化物都得到了细化,弯曲强度达到3580 MPa,硬度达到HRC58,抗划伤性能得到显著增强。

With high-energy wet ball milling M2 high-speed steel(HSS) powder and ferrovanadium alloy,an in-situ synthesized core-shell MC carbides reinforced M2 HSS was prepared via vacuum sintering.The phase,morphology and composition distribution of the milled composite powders,and the evolution of the sintered microstructure with the temperature and the associated mechanical properties before and after heat treatment were investigated.The ground powders were fully refined into lamellae and aggregates with V-element evenly distributed inside.Almost full densification(~99.2% relative density) of the modified M2 steel was achieved at 1180 ℃ by supersolidus liquid phase sintering.Near-spherical MC carbides and irregular M_(6C) carbides were dispersed within the HSS matrix,and the MC developed a core-shell structure due to the solidification of the sintering liquid.Both the matrix grains and carbides of the sintered alloy had been refined by heat treatment,reaching satisfactory bending strength of 3580 MPa and hardness of HRC58,and enhancing the scratch resistance significantly.