晶粒长大抑制剂VC对原位生成WCoB-TiC-Co复相金属陶瓷的影响

为细化WCoB-TiC-Co复相金属陶瓷晶粒，改善其组织, 提高其力学性能，以WC、TiB2和Co粉末为主要原材料，采用真空液相原位反应烧结工艺，在1 400 ℃真空烧结炉中制备了WCoB-TiC-Co复相金属陶瓷.利用FE-SEM、EDS和XRD等技术，研究了不同含量的晶粒长大抑制剂VC对WCoB-TiC-Co复相金属陶瓷组织、物相构成、硬度、密度、耐磨性及抗弯强度和断口形貌等性能的影响.结果表明：添加适量的VC能有效细化WCoB-TiC-Co复相金属陶瓷晶粒，使得材料获得更均匀细小的微观组织, 增加材料韧性和断口不平整性, 增强材料抗弯强度，并且提高硬度、密度和耐磨性; 当VC的质量分数增加到0.9%时，金属陶瓷的晶粒平均尺寸可细化到约1.3 μm，硬度随之升高到91.5 HRA，抗弯强度达到794 MPa; 但VC的质量分数继续增加到1.2%、1.5%时，其硬度、密度、耐磨性及抗弯强度均会有所降低.
In order to refine the grain of WCoB-TiC-Co double phase cermet and improve its microstructure and mechanical properties, using WC, TiB2 and Co powders as main raw materials, WCoB-TiC-Co multiphase metal-ceramics were prepared by in-situ liquid-phase reaction sintering at 1 400 ℃ in the vacuum furnace. The effect of contents of VC grain growth inhibitor on microstructure, phase composition, hardness, density, wear resistance, bending strength and the fracture surface of multiphase metal-ceramics were studied by FE-SEM, EDS and XRD. The results show that, with the addition of a proper VC content, the grain growth of WCoB-TiC-Co multiphase metal-ceramics was effectively suppressed, and the toughness, fracture unevenness, bending strength, hardness and wear resistance of the materials were enhanced. When 0.9wt.% VC was added, the average grain size of WCoB-TiC-Co multiphase metal-ceramics was only 1.3 μm, and, the hardness and the bending strength were 91.5 HRA and 794 MPa, respectively. As the content of VC increased from 1.2wt.% to 1.5wt.%, the hardness, density, wear resistance and bending strength of WCoB-TiC-Co multiphase metal-ceramics reduced gradually.