(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 在1450 ℃下通过低压烧结制备5种0.83~15.03 μm不同WC粉末粒度的WC-15%Fe-5%Ni(质量分数)硬质合金，并通过SEM、XRD、EDS、力学性能测试仪、磨损试验机和电化学工作站研究WC粉末粒度对合金的显微组织和性能的影响。结果表明:随WC粉末粒度的减小，合金的WC晶粒尺寸减小，抗弯强度和硬度升高，断裂韧性降低，耐磨性能提高，耐酸性溶液腐蚀性能变差;当WC粒度较大时，合金的断裂方式主要为穿晶断裂;当WC粒径较小时，断裂方式主要为沿晶断裂;当WC粉末粒度为1.31 μm时，硬质合金的综合性能最好，抗弯强度、硬度、断裂韧性、磨损率和自腐蚀电流密度分别达到2717 MPa、960 MPa、10.7 MPa？m1/2、6.986003×10-7 mm3/(N？m)和3.43698×10-5 A/cm2。
关键字: WC粒度;WC-Fe-Ni硬质合金;微观组织;力学性能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The WC-15%Fe-5%Ni cemented carbides with five different WC particle sizes ranging from 0.83-15.03 μm were fabricated by 1450 ℃ sinter-HIP sintering. The effects of WC particle size on the microstructure and properties of cemented carbides were investigated by SEM, XRD, EDS, mechanical property tester, wear testing machine and electrochemical workstation. The results show that, with the particle size of WC decreasing, the WC grain size decreases, the bending strength and hardness increase, the fracture toughness decreases, the acidic corrosion resistance decreases, wear resistance increases. The fracture mold of cemented carbides with larger WC grain size is mainly transgranular fracture, but the fracture mold of cemented carbides with smaller WC grain size is mainly intergranular fracture. When WC particle size is 1.31 μm, the combination properties of alloy are the best. The bending strength, hardness, fracture toughness, wear rate and the corrosion current densities are 2717 MPa, 960 MPa, 10.7 MPa？m1/2, 6.986003×10-7 mm3/(N？m) and 3.43698×10-5 A？cm-2, respectively.
Key words: WC powder; WC-15%Fe-5%Ni cemented carbide; microstructure; mechanical property
