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、TiB_2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1.3μm,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.

Effect of grain growth inhibitor VC on in situ formation of WCoB-TiC-Co multiphase metal-ceramics

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 metalceramics reduced gradually.