合金添加剂对WC基硬质合金氧化行为及其关联特性的影响

Effects of alloy additives on oxidation behavior and correlative characteristics of WC-based cemented carbides

为了同步改善合金的高温抗氧化性能及物理与力学性能,设计WC-6Co-6Ni、WC-6Co-6Ni-1Cr_(3)C_(2)、WC-6Co-6Ni-1CeO_(2)和WC-12Co-1CeO_(2)等4组WC基硬质合金,分别对应1^(#)~4^(#)合金,对比研究合金的微观结构、物理与力学性能和700℃连续16 h的氧化行为。结果表明,CeO_(2)弥散相的存在不会导致WC基硬质合金强度降低,合金硬度遵循复合材料硬度及晶粒度和各相体积分数的耦合作用规律。4组合金中,4^(#)合金的硬度最高,其次为2^(#)合金,Co、Ni黏结金属对硬质合金硬度的影响显著。Cr_(3)C_(2)和CeO_(2)添加剂均可显著改善700℃下合金的抗氧化性能,但Cr_(3)C_(2)的改善效果明显优于CeO_(2)。在WC基硬质合金中添加适量的Cr_(3)C_(2)和CeO_(2),并用Ni部分替代Co,可实现对合金高温抗氧化性能及物理与力学性能同步改善。

To explore the methods to improve the oxidation resistance at high temperature and the physical and mechanical properties simultaneously.Thus,this research designed WC-6Co-6Ni,WC-6Co-6Ni-1Cr_(3)C_(2),WC-6Co-6Ni-1CeO_(2) and WC-12Co-1CeO_(2) WC-based cemented carbides,corresponding to alloys 1^(#)−4^(#),respectively.The microstructure,physical and mechanical properties and oxidation behavior of the alloys at 700℃for 16 h were investigated by comparison.The results show that the presence of rare earth-containing oxide dispersion phase in the alloy does not lead to the decrease of alloy strength,and the alloy hardness follows the coupling law of hardness,grain size and volume fraction of the phase components.The hardness of alloy 4^(#)is the highest,followed by alloy 2^(#).The influence of Co and Ni binder metals on the hardness of cemented carbides is significant.Both Cr_(3)C_(2) and CeO_(2) can significantly improve the oxidation resistance of the alloys at 700℃,but the improvement effect of Cr_(3)C_(2) is better than that of CeO_(2).The high temperature oxidation resistance and physical and mechanical properties of WC-based cemented carbide can be improved synchronously by adding appropriate amount of Cr_(3)C_(2) and CeO_(2),and using Ni to partially replace Co.