Cr_(3)C_(2)/VC复合抑制剂比例对WC-10%Co超细晶硬质合金微观结构和力学性能的影响

Effect of Cr_(3)C_(2)/VC Composite Inhibitor Ratio on Microstructure and Mechanical Properties of Ultrafine Grained WC-10%Co Cemented Carbide

本文以WC-10%Co为研究对象,添加质量分数1.0%的Cr_(3)C_(2)/VC复合抑制剂,在1410℃下烧结1 h,制备了WC-10%Co-Cr_(3)C_(2)/VC超细晶硬质合金,研究了Cr_(3)C_(2)/VC复合抑制剂比例对物相组成、WC晶粒尺寸和粒度分布、WC三维形貌及力学性能的影响。结果表明:随Cr_(3)C_(2)含量的减少和VC含量的增加,WC平均晶粒尺寸先快速后缓慢减小,WC粒度分布不断变窄;WC形貌由三棱柱向台阶三棱柱转变,WC(0001)晶面上的台阶数量不断增加,这些台阶会显著降低合金的断裂韧性和抗弯强度;WC-10%CoCr_(3)C_(2)/VC超细晶硬质合金的硬度先快速后缓慢增加,而断裂韧性和抗弯强度先快速后缓慢降低;当w(Cr_(3)C_(2))∶w(VC)=4∶1时,WC-10%Co-0.8%Cr_(3)C_(2)-0.2%VC硬质合金具有最优的综合性能,其维氏硬度、断裂韧性和抗弯强度分别为17.05 GPa、9.26 MPa·m^(1/2)和3650 MPa。

In this paper,WC-10%Co was studied,and ultrafine grained WC-10%Co-Cr_(3)C_(2)/VC cemented carbide was prepared by adding Cr_(3)C_(2)/VC composite inhibitor with a mass fraction of 1.0% and sintering at 1410℃ for 1 h.The effects of the Cr_(3)C_(2)/VC composite inhibitor ratio on phase composition,WC grain size and particle size distribution,WC threedimensional morphology,and mechanical properties were studied.The results show that with the decrease in Cr_(3)C_(2) content and the increase in VC content,the average grain size of WC decreases rapidly and then slowly,and the particle size distribution of WC continues to narrow.The morphology of WC changes from a triangular prism to a stepped triangular prism,and the number of steps on the WC(0001)crystal surface increases continuously.These steps will reduce the fracture toughness and bending strength of the alloy significantly.The hardness of ultrafine grained WC-10%Co-Cr_(3)C_(2)/VC cemented carbide increases rapidly and slowly at first,while the fracture toughness and bending strength decrease rapidly and then slowly.When Cr_(3)C_(2)∶VC=4∶1(mass ratio),WC-10%Co-0.8%Cr_(3)C_(2)-0.2%VC cemented carbide has the best comprehensive properties,and its Vickers hardness,fracture toughness,and bending strength are 17.05 GPa,9.26 MPa·m^(1/2),and 3650 MPa,respectively.