纳米WC/Co硬质合金粉末烧结早期的晶粒长大研究

Study of Grain Growth of Nanocrystalline WC/Co Powder in theEarly Stage of Sintering

研究了纳米晶粒WC/Co硬质合金烧结早期的晶粒长大问题,利用X射线衍射、TEM等技术对烧结过程中晶粒变化情况进行分析,并在此基础上探讨了烧结早期的晶粒长大机制。实验结果表明:WC晶粒长大在加热过程已经发生;晶粒开始长大温度为1000℃,在1100℃部分晶粒长大到100nm;在1200℃,有更显著的晶粒长大发生,有些尺寸达到400nm。烧结过程中WC晶粒形状变得规则化。烧结早期WC晶粒长大是在晶粒旋转合并机制与局部液相烧结机制共同作用下完成。

Study is made of the grain growth of tungsten carbide (WC)in the early stage of sintering TEM and XRD analysis is made of the change of grain during sintering,based on which the mechanisms of grain growth are discussed. Results showed that grain growth occurred during heating at 1 000 ℃ with some grains grown up to 100 nm at 1 100℃.At 1 200℃,even more dramatic grain growth occurred with some grains up to 400 nm.The shape of WC grains become regular during sintering.And WC grains are grown up based on the grain rotation combination mechanism and local liquid-phase sintering in the early stages of sintering.