碳含量对WC-9Ni-1Cr细晶硬质合金组织结构及性能的影响  

Effect of carbon content on microstructures and properties of WC-9Ni-1Cr cemented carbide

作　　者：董凯林[1] 曹万里[1] 时凯华[1,2] 江庆[1] 高建[1] 

机构地区：[1]自贡硬质合金有限责任公司,自贡643011 [2]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2015年第3期449-455,共7页Materials Science and Engineering of Powder Metallurgy

摘　　要：通过添加W粉或C粉调整WC原料粉末的总碳含量（质量分数）为6.04%~6.16%,采用低压烧结法制备WC-9Ni-1Cr细晶硬质合金。采用光学金相显微镜、X射线衍射、扫描电镜等,研究碳含量对WC-9Ni-1Cr细晶硬质合金组织结构及性能的影响。结果表明：在WC-Ni系合金中添加适量的Cr元素,得到无磁WC-Ni硬质合金,并且其无磁特性不随合金中碳含量的变化而发生转变。WC粉末的总碳含量为6.04%~6.16%时WC-9Ni-1Cr细晶硬质合金为二相区的正常组织,只存在WC相和Ni相,没有石墨夹杂或η相;而且在此二相区范围内WC的碳含量变化对WC-9Ni-1Cr细晶硬质合金的耐腐蚀性没有明显影响。随WC粉末的碳含量增加,合金硬度（HRA）与密度都逐渐降低,但降低幅度较小,而合金的抗弯强度逐渐提高。碳含量由6.04%增加至6.16%时,抗弯强度由2 250 MPa提高到2 850 MPa,提高26.6%。A series of WC-9Ni-1Cr microcrystalline cemented carbides with WC carbon content range of 6.04% to 6.16% by adjusting the adding value of W and C powder were prepared by low-pressure sintered. The microstructures and properties were observed and tested using optical microscope, X-ray diffraction and SEM. The results show that the WC-Ni cemented carbide would be non-magnetic when adding an appropriate amount of Cr element, and the carbon content has no effect on the non-magnetic property of WC - Ni alloy. It is found that when the carbon content of WC powder is in the range of 6.04% to 6.16%, the microstructures of all the WC-Ni cemented carbides are normal with only WC and Ni phases, without graphite and η phases. In the WC＋γ two-phase region, the carbon content has no effect on the corrosion resistance. With increasing carbon content of WC powder, the hardness and density decrease, but the change is slight. The bending strength increases gradually with increasing carbon content, and when the carbon content of WC powder increases from 6.04% to 6.16%, the bending strength increases from 2 250 MPa to 2 850 MPa, increasing by 26.6%.

关 键 词：碳含量 硬质合金 微观结构 性能 

分 类 号：TF124[冶金工程—粉末冶金]