微波烧结制备WC-8Co硬质合金过程中的脱碳行为研究

碳平衡在硬质合金的制备过程中具有非常重要的意义,脱碳和渗碳都会对合金的显微组织和力学性能造成不良影响。主要研究了在微波烧结条件下,合金脱碳因素(气氛、氧含量、烧结工艺等)对WC-Co硬质合金显微组织的影响。结果表明:氮气和氢气会造成合金表层脱碳,随着烧结温度的提高和保温时间的增加脱碳层变厚;压坯中较高的氧含量会使合金表层形成多达五层的脱碳组织;最后讨论了在微波加热条件下WC-Co合金脱碳的动力学和热力学机制。

Decarburization of WC-8Co Preparation under Microwave Sintering

Carbon balance is the most important factor in preparing cemented carbides. Slight change of total carbon content leads the decarburization or graphitization, which has an unfavorable or detrimental influence on alloy microstructure. Carbon content affecting factors including nitrogen, hydrogen and oxygen content in powder mixture on WC-Co microstructure are studied. The results show that the surface decarburization layer-structure forms in nitrogen and hydrogen atmospheres during the microwaves sintering process. The decarburization layers could be increased with sintering temperature and soaking time. The number of decarburization layers is increased to five due to the high oxygen content in mixture. Decarburization mechanism during microwave sintering is discussed.