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以超粗碳化钨粉和球形钴粉为原料,通过在粗晶WC-10%Co基体中加入细微Al2O3颗粒,通过低压烧结制备粗晶硬质合金。采用金相显微镜、扫描电子显微镜观察合金微观形貌,测定抗弯强度、冲击韧性、硬度等力学性能。结果表明:添加一定含量的Al2O3可以使硬质合金的晶粒细化,晶粒形貌趋向球化而且分布均匀,因为球化WC晶粒和较大的Co相平均自由程的存在使得裂纹产生偏转、分叉和不连续现象,从而提高硬质合金的抗弯强度,冲击韧性和耐磨性。添加是质量分数0.4%的Al2O3使合金的抗弯强度从2 492 MPa提升到2 832 MPa,冲击韧性从6.18 J/cm2提升到7.52 J/cm2。
Using coarse tungsten carbide powder and spherical cobalt powder as raw materials, the coarse-grained cemented carbide was prepared by adding fine Al2O3 particles into the coarse-grained WC-10% Co matrix by low-pressure sintering. The microstructure of the alloy was observed by optical microscope and scanning electron microscope. The mechanical properties such as flexural strength, impact toughness and hardness were measured. The results show that adding a certain amount of Al2O3 can refine the grain of the cemented carbide and the grain morphology tends to be spheroidized and evenly distributed because of the existence of cracks caused by the mean free path of the spheroidized WC grains and the larger Co phase Deflection, bifurcation and discontinuities, thereby increasing the flexural strength of hardmetal, impact toughness and wear resistance. With the addition of 0.4% Al2O3, the bending strength of the alloy increased from 2 492 MPa to 2 832 MPa and the impact toughness increased from 6.18 J / cm2 to 7.52 J / cm2.