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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。
In order to obtain high-performance carbide particle reinforced materials, the use of powder metallurgy method to prepare powder metallurgy steel. The influence factors of the microstructure and properties of the material were studied by optical microscopy, scanning electron microscopy, energy spectrum analyzer and mechanical property testing. The results show that there are M2C acicular carbides and M6C massive carbides in the material. The morphology of the carbide-reinforced particles has a significant effect on the material properties. When the sintering temperature is low, the material density is low and the carbide morphology is massive. Sintering temperature increases, the material density increased significantly, carbide morphology from massive to acicular changes. However, acicular carbides form semi-continuous network structures on the grain boundaries, reducing material properties. Long time annealing can make the grain boundary network carbide fracture and spheroidization, significantly improve the performance of the material. After heat treatment, the hardness and strength of the material increase, but the toughness decreases. Sintering + annealing + heat treatment process to prepare a good overall performance carbide particle reinforced powder metallurgy steel.