两步烧结对超细晶WC-4%Co硬质合金微观组织及性能的影响  

Influence of Two-step Sintering Method on Microstructure and Performances of Ultrafine-grained WC-4%Co Cemented Carbide

作　　者：刘斌[1,2] 孔德方[1,2] 戴炳蔚[1,2] Liu Bin;Kong Defang;Dai Bingwei(Zhuzhou Cemented Carbide Group Corp.Ltd.,Zhuzhou Hunan 412000,China;State Key Laboratory of Cemented Carbide,Zhuzhou Hunan 412000,China)

机构地区：[1]株洲硬质合金集团有限公司,湖南株洲412000 [2]硬质合金国家重点实验室,湖南株洲412000

出　　处：《硬质合金》2019年第6期406-413,共8页Cemented Carbides

基　　金：株洲市科技计划项目：系列木质复合材料加工用高端硬质合金刀具材料的开发(2017);湖南省省市联合基金项目：超细硬质合金液相烧结过程中的晶粒生长行为及均匀化控制（2017JJ4075）

摘　　要：采用瞬时烧结法确定了超细晶WC-4%Co硬质合金在烧结过程中矫顽磁力突变温度,据此设计了该合金两步烧结工艺曲线。采用传统烧结方法和两步烧结方法制备超细晶WC-4%Co合金,研究了两步烧结方法对超细硬质合金的微观组织、力学性能和切削性能的影响规律。结果表明:超细晶WC-4%Co合金矫顽磁力突变的温度点在1 450℃以上。采用传统烧结方法制备的超细晶WC-4%Co合金中WC晶粒的三维形貌为多台阶层状结构,WC晶粒尺寸分布范围宽;两步烧结方法制备的WC-4%Co合金中WC的晶粒三维形貌发育为单层和三棱柱混合结构,WC晶粒尺寸分布范围窄。由于细颗粒WC溶解-析出行为的充分进行,两步烧结方法制备的合金硬度略微下降,断裂韧性有较大幅度提高。铣削试验结果表明:两步烧结制备的超细晶WC-4%Co合金木工铣刀的的抗崩刃性能及铣削寿命高于传统方法烧结的合金产品。The abrupt temperature of coercive force during sintering process of WC-4%Co cemented carbide was investigated by instantaneous sintering, and the two-step sintering process curve was designed. The WC-4%Co ultrafine grained cemented carbides were prepared using traditional sintering method and two-step sintering method by sinter-HIP furnace. The influence of two-step sintering on microstructure, mechanical properties and cutting performance of the WC-4%Co ultrafine grained cemented carbide was investigated. The results show that the three-dimensional grain morphology of WC has a multi-layered structure using traditional sintering method. For the alloy prepared by the two-step sintering method, the morphology of WC grain has a mixture structure, which contains both single-layer and triangular prism structure. Due to the full WC dissolution-precipitation behavior of fine particles, the hardness of the alloy prepared by twostep sintering method is slightly decreased, while the fracture toughness is greatly improved. The milling experiment results show that the average milling life and stability of WC-4%Co ultrafine grained cemented carbide prepared by two-step sintering is superior to that of conventionally sintered cemented carbide.

关 键 词：瞬时烧结 晶粒形貌 矫顽磁力 两步烧结 

分 类 号：TG1[金属学及工艺—金属学]