(1. 四川理工学院 机械工程学院，宜宾 644000；
2. 自贡硬质合金有限责任公司，自贡 643011；
3. 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 以冲模用高钴ZL40.5硬质合金作为研究对象，采用扫描电镜(SEM)、X射线衍射(XRD)等方法对系列热处理试样进行分析，基于晶体学理论并结合Image J、Jade软件研究ZL40.5硬质合金微观组织结构参数(粘结相体积分数、晶粒度、邻接度、残余应力及晶格常数)、断口形貌及其性能。结果表明：淬火处理使WC晶粒形貌变圆润，降低应力集中的发生，减少断裂源；淬火回火处理后，粘结相中α-Co含量大幅提升，WC邻接度降低，合金在保证硬度的同时强度和韧性得到提升；热处理后合金断裂以沿晶和韧性复合形式为主，淬火回火后表面压应力提升最高。
关键字: 硬质合金；热处理；微观组织；断口形貌；综合性能
（1. College of Mechanical Engineering, Sichuan University of Science and Technology, Yibin 644000, China;
2. Zigong Cemented Carbide Corporation Limited, Zigong 643011, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The effects of heat treatment processing on microstructure of high cobalt ZL40.5 cemented carbide synthesized by gas pressing sintering were investigated using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Based on the crystallography theory and combined with Image J and Jade software, the properties of the alloy, such as hardness, bending strength and residual stress, were measured. The results show that the quenching treatment makes the morphology of WC grain round and smooth, reduces the occurrence of stress concentration and reduces the source of fracture. After quenching and tempering, the content of α-co in the bonding phase increases greatly, WC adjacency decreases, and the strength and toughness of the alloy are improved while the hardness is guaranteed. The fracture of the alloy after heat treatment is mainly in the form of intergranular and ductile composite，after quenching and tempering, the surface compressive stress increases to the highest.
Key words: cemented carbide; heat treatment; microstructure; fracture morphology; combination property
