高性能颗粒强化粉末冶金钢的研制

Preparation of PM particulate reinforced steel with high properties

为了获得高性能的碳化物颗粒强化材料,采用粉末冶金方法制备了粉末冶金钢。采用光学显微镜、扫描电镜、能谱分析仪和力学性能检测研究了材料组织与性能的影响因素。结果表明:材料中主要存在M2C针状碳化物和M6C块状碳化物。碳化物强化颗粒的形貌对材料的性能影响显著。烧结温度较低时,材料密度低,碳化物形貌为块状。烧结温度升高,材料密度明显提高,碳化物形貌从块状向针状转变。但是,针状碳化物在晶界上形成半连续网络组织,降低材料性能。长时间高温退火能使晶界上网状碳化物断裂并球化,显著提高材料的各项性能。热处理后,材料的硬度和强度提高,但韧性下降。采用烧结+退火+热处理工艺,制备了综合性能好的碳化物颗粒强化粉末冶金钢材料。

Particulate reinforced iron-based materials with high properties were prepared by powder metallurgy processing technique.The influence factors on microstructure and properties of PM particulate reinforced steel were studied by optical microscopy,scanning electron microscopy,energy dispersive spectroscopy and mechanical test.The results show that,M2C needle-like carbides and M6C bulk carbides exit in the materials.The carbides morphology influences the materials microstructure and properties obviously.With the increase of the sintering temperature,the materials density increases and the bulk carbides change to be the needle-like carbides.The needle-like carbides around the crystal borders are harmful to the steels properties.After long time annealing,because of the most of needle-like carbides decomposed,the steels properties increase evidently.After heat treatment,the hardness and strength increase,but toughness decreases.A high properties PM particulate reinforced steel was attained.