热压固结与传统液相烧结对WC-20Co-1Y2O3硬质合金组织结构与性能的影响

研究了低于共晶温度下热压固结与传统液相烧结对用超细原料制备的WC-20Co-1Y2O3硬质合金组织结构与性能的影响.研究结果表明热压固结的合金具有组织结构致密、细小、均匀、各向同性的特点,但是合金中存在较多的钴池,采用超细原料、较高的液相烧结温度制备高钴硬质合金,合金中的稀土不能对合金中晶粒非均匀长大产生有效的抑制作用,合金晶粒组织呈现双模结构,其中粗大WC大多为极状晶,因而合金韧性较高.

WC-20Co-1Y2O3 cemented carbide by hot-press and liquid phase sintering

The effect of hot-press at the temperature below the eutectic melting temperature and conventional liquid phase sintering on the structures and properties of WC-20Co-1Y_2O_3 cemented carbide prepared from ultrafine raw materials was studied, It is shown that hotpressed alloy has the character of fine, homogeneous and isotropic properties. However, the fine and fully-densified structure is at the cost of large amount of cobalt-lake (un-evenly-distributed binder phase). Rare earth in the alloy cannot play the role of grain growth inhibitor when cemented carbide with high content cobalt and fine raw material is sintered at high liquid phase sintering temperature, which is the reason for bi-model structure in the alloy. In the high temperature liquid phase sintered alloy, quite a part of the large grains has the character of platelet, which promises higher toughness.