WC硬质合金颗粒堆焊烧损的机理

采用扫描电镜、X射线衍射及电子探针等测试分析手段，研究了WC硬质合金堆焊过程的熔化烧损特征和机制。试验结果表明，堆焊过程中不可避免WC硬质合金的烧损，烧损的基本特征是硬质合金边缘的粘结相熔化、碳化物颗粒的增大、单晶WC之间的间距增加。硬质合金烧损形式主要有颗粒边缘熔化、溶解烧损、合金元素的扩散和反应烧损。硬质合金烧损的机理为硬质合金边缘的碳化物产生分解，与胎体金属之间发生元素扩散。形成具有一定浓度梯度的扩散层，扩散层外沿原子浓度高的区域发生组织变化，形成新的化合物，降低硬质合金的性能，烧损的程度与硬质合金的种粒、粒度、含量以及堆焊方法等因素有关。

The Heat Damage Mechanism of WC Cemented Carbide for Hardfacing

Using SEM,X ray and EPMA,the heat damage characteristic and mechanism of WC cemented carbide in the course of hadfacing have been investigated.The results showed that the heat damage of cemented carbide was inevitable.The main characteristic of heat damage was the decompose and diffusion of carbide .The grain of fringe carbide grew up ,reseparated out and a new phase was formed.The type of heat damage for WC cemented carbide was melting and dissolve of carbide,diffusion and reaction of element.The mechanism of heat damage for cemented carbide was the element diffusion and chemical reaction between cemented carbide and matrix metal.The diffused zoom and new phase were formed at the interface of cemented carbide and matrix.The kind,size,content and method of hardfaceing all directly affected the level of heat damage.