WC碳含量对WC-TiC-(Co,Ni)硬质合金组织及性能的影响  

Effect of Carbon Content of WC on the Microstructure and Properties of WC-TiC-(Co,Ni)Cemented Carbide

作　　者：王晓灵[1] 熊超伟 

机构地区：[1]自贡硬质合金有限责任公司成都分公司,四川成都610100

出　　处：《四川冶金》2015年第4期48-54,66,共7页Sichuan Metallurgy

摘　　要：采用在超粗WC及Co粉末中掺加预制含TiC的细晶粒混合料粉末共同球磨混合的方法,制备了WC-0.8%TiC-17.5%(Co,Ni)(质量分数,下同)硬质合金,超粗WC粉末原料的配碳量在5.85%~6.21%之间变化。通过对合金物理、力学性能及金相组织的检测分析和对比,研究了WC的碳含量对WC-0.8TiC-17.5(Co,Ni)硬质合金性能及组织的影响。结果显示,随着WC碳含量的降低,合金的比饱和磁化强度(Ms.)减小,密度、磁力(Hc.)及硬度(HRA)增大,而抗弯强度(TRS)呈先增大后减小的趋势,冲击韧性(Ak)在WC碳含量为5.95%~6.21%时变化不明显,为4.50±0.15J/cm2,但在WC碳含量为5.85%时,急降至3.08J/cm2。实验合金组织均呈三相双晶结构,粗大的WC晶粒以及细小的β相((W,Ti)C)晶粒均匀散布在Co粘结相中。随着WC碳含量的降低,粗大WC晶粒的结晶完整性变差,硬质相平均晶粒度减小,β相粒度变化不明显约为1.0μm,当WC碳含量降至5.85%时,硬质相的粒径离差系数显著增大,同时出现了少数异常粗大的β相晶粒。=In this study, a kind of WC-0.8%TiC-17.5^（Co,Ni） （mass fraction, hereinafter） cemented carbide was manufactured, using the method of blending preparation-grade-powder containing TiC with extra-coarse WC and Cobalt raw powders by ball-milling. The carbon content of extra-coarse WC powder varies from 5.85% to 6.21%. Then, the effect of carbon content of WC powder on the microstructure and properties of sintered alloy have been studied by mechanical and magnetic properties testing and microstructure observation. It was found that the weight-specific magnetic saturation （Ms.） decrease, and the density, coercive force （Hc.） and hardness （HRA） rise with decreasing carbon content. While the transverse rupture strength （TRS） increases firstly, then decreases when the carbon content decreases. The impact toughness（Ak）maintains on the value of 4.50±0.15 J/cm2 when the carbon content varies between 6.21% and 5.95%, but decreases sharply to 3.08 J/cm2, as the carbon content decreasing to 5.85%. The microstructure displays a dual-grained structure with coarse WC and fineβphase （ （W, Ti）C grains） embed in the Co-based binder. When the carbon content reduces, the crystal integrality of coarse WC grains deteriorates, and the average size of hard phase decreases, while the size oft？phase maintains about 1.0μm. The size dispersion coefficient of hard particles increases observably, meanwhile some abnormal coarseβphase particles appear, when the carbon content of WC reduces to 5.85%.

关 键 词：硬质合金 碳含量 双晶结构 显微组织 性能 

分 类 号：TG135.5[一般工业技术—材料科学与工程]