(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 在1450 ℃下低壓燒結(jié)制備5 種不同F(xiàn)e/Ni比(質(zhì)量比)的WC-Fe-Ni硬質(zhì)合金，通過SEM、TEM、XRD、力學(xué)性能測試和電化學(xué)測試研究Fe/Ni比對硬質(zhì)合金的顯微組織和性能的影響。結(jié)果表明：隨Fe/Ni比增大，晶粒尺寸先下降后上升； Fe/Ni比為3:1時，合金晶粒尺寸最小，為1.24 μm；合金抗彎強度變化趨勢和晶粒尺寸變化呈反比；硬度不斷提高，斷裂韌性變化與燒結(jié)致密度變化均保持先上升后下降趨勢；在Fe/Ni比為3:1時，合金斷裂方式主要為沿晶斷裂，在Fe/Ni比不等于3:1時會出現(xiàn)較多穿晶斷裂；合金耐酸性溶液腐蝕能力不斷變差。當Fe/Ni比為 3:1時，合金的綜合性能最好，其硬度、抗彎強度、斷裂韌性、腐蝕電流密度分別達到934HV、3047 MPa、23.3 MPa？m1/2、3.98×10-5 A/cm2。
關(guān)鍵字: WC-Fe-Ni 硬質(zhì)合金；Fe/Ni比；WC 晶粒大小；微觀組織；力學(xué)性能；耐蝕性能
（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
