(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 在1450 ℃下低压烧结制备5 种不同Fe/Ni比(质量比)的WC-Fe-Ni硬质合金，通过SEM、TEM、XRD、力学性能测试和电化学测试研究Fe/Ni比对硬质合金的显微组织和性能的影响。结果表明：随Fe/Ni比增大，晶粒尺寸先下降后上升； Fe/Ni比为3:1时，合金晶粒尺寸最小，为1.24 μm；合金抗弯强度变化趋势和晶粒尺寸变化呈反比；硬度不断提高，断裂韧性变化与烧结致密度变化均保持先上升后下降趋势；在Fe/Ni比为3:1时，合金断裂方式主要为沿晶断裂，在Fe/Ni比不等于3:1时会出现较多穿晶断裂；合金耐酸性溶液腐蚀能力不断变差。当Fe/Ni比为 3:1时，合金的综合性能最好，其硬度、抗弯强度、断裂韧性、腐蚀电流密度分别达到934HV、3047 MPa、23.3 MPa？m1/2、3.98×10-5 A/cm2。
关键字: WC-Fe-Ni 硬质合金；Fe/Ni比；WC 晶粒大小；微观组织；力学性能；耐蚀性能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:WC-Fe-Ni cemented carbides with five kinds of Fe/Ni ratio were prepared by 1450 ℃ sinter-HIP sintering to study the effects of Fe/Ni ratio on the microstructure and properties by SEM, XRD, mechanical performance test and electrochemical test. The results show that with the increase of Fe/Ni ratio, the grain size firstly decreases and then increases. The grain size reaches the finest (1.24 μm) with Fe/Ni ratio of 3:1. And with the increase of Fe/Ni ratio, the changing trend between bending strength and grain size is inverse, the hardness increases continuously, both of fracture toughness and sintering density firstly increase and then decrease. When Fe/Ni ratio is 3:1, fracture mode is mainly intergranular fracture. Except for the alloy with Fe/Ni ratio of 3:1, more transgranular fracture appears. The acidic corrosion resistance ability gets worse continuously. When Fe/Ni ratio is 3:1, WC-Fe-Ni alloy exhibits optimum properties, the hardness, bending strength , fracture toughness and corrosion current density are 3047 MPa, 934HV, 23.3 MPa？m1/2 and 3.98×10-5 A/cm2, respectively.
Key words: WC-Fe-Ni cemented carbide; Fe/Ni ratio; WC grain size; microstructure; mechanical property; corrosion property
