VC含量对超细硬质合金微观组织和性能的影响  

Effect of VC Content on the Microstructure and Properties of Ultrafine Cemented Carbide CHEN Xuanheng1,LIU Changbin2,LIU Fengguang2,LUO Shuanglan2,

作　　者：陈轩恒 刘昌斌 刘风光 罗双兰 颜练武 伍小波[1] 彭英彪[1] CHEN Xuanheng;LIU Changbin;LIU Fengguang;LUO Shuanglan;YAN Lianwu;WU Xiaobo;PENG Yingbiao(National&Local Joint Engineering Research Center for Advanced Packaging Material and Technology,Hunan University of Technology,Zhuzhou Hunan 412007,China;Weikai Cutting Tools Co.,Ltd.,Zhuzhou Hunan 412007,China)

机构地区：[1]湖南工业大学先进包装材料研发技术国家地方联合工程研究中心,湖南株洲412007 [2]株洲韦凯切削工具有限公司,湖南株洲412007

出　　处：《湖南工业大学学报》2025年第3期98-104,共7页Journal of Hunan University of Technology

基　　金：湖南省自然科学基金资助项目(2023JJ50182,2022JJ50086);湖南省教育厅科研基金资助项目(21B0542)。

摘　　要：WC-Co基超细晶硬质合金具优异综合力学性能,成为制备高性能切削刀具的理想材料。为改善WC-Co基硬质合金的综合性能,制备了具不同碳化钒(VC)含量的超细硬质合金,研究了VC添加量对(V,W)C立方相团聚、烧结过程中WC三维晶粒形貌演变及力学性能的影响,并利用热力学计算对(V,W)C立方相团聚现象进行理论分析。结果表明:VC在黏结相的固溶度较小,当VC添加质量分数为0.3%时,黏结相中过饱和的V在液态黏结相中迅速析出,导致组织中出现(V,W)C团聚立方相;随着VC添加量继续增加,V的过饱和析出量和析出温度进一步增加,导致团聚组织尺寸显著增加,严重影响了材料的组织均匀性;VC在WC/Co界面的偏析导致WC晶粒呈现台阶状三棱柱形貌,该形貌随VC添加量和烧结温度的增加而更显著;随着VC添加质量分数从0.1%增至0.6%,合金的矫顽磁力显著增加,维氏硬度亦呈上升趋势,而断裂韧性则呈下降趋势。当VC添加质量分数为0.6%时,合金展现出最佳综合性能,维氏硬度和断裂韧性分别为17.9 kN/mm^(2)和8.9 MPa·m^(1/2),相对磁饱和和矫顽磁力分别为88.5%和31.57 kA/m。WC-Co based ultrafine cemented carbide has become an ideal material for manufacturing high-performance metal cutting tools due to its excellent comprehensive mechanical properties.In order to improve the comprehensive properties of WC-Co based cemented carbides,ultra-fine cemented carbide with different contents of vanadium carbide(VC)were prepared,and the effects of VC addition on the(V,W)C cubic phase agglomeration and its morphology evolution as well as mechanical properties of three-dimensional WC grain during sintering process were systematically studied.Additionally,thermodynamic calculations were utilized for theoretical analysis of the agglomerative of(V,W)C cubic phase.The results showed that the solid solubility of VC reached saturation and agglomerative(V,W)C cubic phase occurred in the microstructure when the addition of VC was up to 0.6%.Further increasing VC content,the size of agglomerated structure significantly increased,which greatly affected the uniformity of the material.The segregation of VC at the WC/Co interface results in WC grains exhibiting a stepped triangular prism morphology.The stepped three-dimensional morphology becomes more pronounced with increasing VC content and sintering temperature.As the VC content increases from 0.1%to 0.6%,the coercivity of the cemented carbide significantly increases,and the Vickers hardness also shows an upward trend,while the fracture toughness decreases.When the VC content reaches 0.6%,the cemented carbide exhibits optimal comprehensive performance,with Vickers hardness and fracture toughness of 17.9 kN/mm^(2) and 8.9 MPa·m^(1/2),respectively,and the relative magnetic saturation and coercivity are 88.5%and 31.57 kA/m,respectively.

关 键 词：WC-CO硬质合金 VC 微观组织 力学性能 热力学计算 

分 类 号：TH135.5[机械工程—机械制造及自动化]