论文部分内容阅读
通过加入2.5%板状WC晶种,制备含板状WC晶粒硬质合金,研究其强韧化机制。结果表明:WC晶粒的各向异性和形状改变诱导的Hall-Petch硬化是硬质合金硬度增加的主要原因。加入板状晶种后,裂纹在扩展过程中出现了明显的穿晶断裂和Co相桥接,增加了裂纹偏转,硬质合金的抗弯强度大大提高。不同Co含量和初始WC粉体粒度制备的含板状WC晶粒硬质合金,穿晶断裂、Co相桥接和裂纹偏转对抗弯强度增加的贡献不同。
By adding 2.5% plate-like WC seed crystals, WC-containing cemented carbide with plate-like shape was prepared and the mechanism of strengthening and toughening was studied. The results show that Hall-Petch hardening induced by anisotropy and shape change of WC grains is the main reason for the increase of hardness of cemented carbide. After the addition of plate seed, the crack appeared obvious transgranular fracture and Co phase bridging during the expansion, which increased the crack deflection and greatly increased the flexural strength of the cemented carbide. The contribution of WC grain cemented carbide with different Co content and initial WC grain size to the increase of flexural strength is different for transgranular fracture, Co phase bridge and crack deflection.