配碳量对超细晶WC-6Co硬质合金组织性能的影响  

Effect of Carbon Addition on the Microstructure and Properties of Ultrafine-Grained WC-6Co Cemented Carbide

作　　者：傅声华 肖森 邓玲玲 吴益群 曾晓路 金家成 FU Sheng-hua;XIAO Sen;DENG Ling-ling;WU Yi-qun;ZENG Xiao-lu;JIN Jia-cheng(Chongyi Zhangyuan Tungsten Co.,Ltd.,Ganzhou 341300,China)

机构地区：[1]崇义章源钨业股份有限公司,江西赣州341300

出　　处：《稀有金属与硬质合金》2025年第2期109-115,共7页Rare Metals and Cemented Carbides

摘　　要：以超细晶WC-6Co-0.7Cr_(3)C_(2)-0.4VC硬质合金为研究对象,分别配制了6组不同配碳量(质量分数)的混合料,经压制、烧结制备出不同碳含量的硬质合金;采用金相显微镜、扫描电镜、磁饱和仪、矫顽磁力计、排水法、维氏硬度计和力学试验机分析了配碳量对硬质合金微观组织以及物理力学性能的影响。结果表明:配碳量为5.74%、5.78%的硬质合金处于WC+Co两相区;当配碳量低于5.74%时,合金基体中出现脱碳相(η相);而当配碳量高于5.78%时,合金基体出现雪花状渗碳相(C相)。随着配碳量的增加,硬质合金的相对饱和磁化强度先逐渐增大后略有降低,矫顽力及密度整体上逐渐下降;维氏硬度逐渐降低,开裂韧性先升高后降低再略有回升,横向断裂强度先急剧升高后逐渐降低。当配碳量控制在5.74%~5.78%时,硬质合金处于WC+Co两相区,可获得较佳的硬度、强度与韧性匹配。配碳量为5.66%的合金断口存在点状脱碳相,该相成为断裂源降低了合金强度和韧性;配碳量为5.74%的两相区合金断口组织形貌均匀,无组织缺陷;配碳量为5.86%的合金断口存在黑色渗碳相,该相降低了合金的强度、硬度和韧性。Using ultrafine-grained WC-6Co-0.7Cr_(3)C_(2)-0.4VC cemented carbide as the research object,six groups of mixed powders with different carbon additions(mass fraction)were blended,and then cemented carbide samples with different carbon contents were fabricated via pressing and sintering.The effects of carbon addition on the microstructure and physical-mechanical properties of the cemented carbide were analyzed using metallographic microscope,scanning electron microscope(SEM),magnetic saturation tester,coercivity meter,water displacement method,Vickers hardness tester,and mechanical testing machine.The results show that the cemented carbides with carbon additions of 5.74%and 5.78%are in the WC+Co two-phase region.When the carbon addition is below 5.74%,the decarburization phase(ηphase)appears in the substrate.When the carbon addition exceeds 5.78%,the snowflake-like carburization phase(C phase)forms.As carbon addition increases,the relative saturation magnetization of the cemented carbide initially rise gradually and then slightly decreases,while coercivity and density generally decline.The Vic-kers hardness progressively decreases,the fracture toughness initially increases,then decreases,and finally slightly recovers,and the transverse rupture strength(TRS)rises sharply before gradually declining.When the carbon addition is controlled within the range of 5.74%to 5.78%,the cemented carbide remains in the WC+Co two-phase region,achieving an optimal balance of hardness,strength,and toughness.The fracture surface of the cemented carbide with a carbon addition of 5.66%exhibits dotted decarburization phase,which acts as fracture origins and reduces the strength and toughness of the cemented carbide.In contrast,the fracture surface of the two-phase cemented carbide with a carbon addition of 5.74%exhibits a uniform microstructure without defects.However,the fracture surface of the cemented carbide with a carbon addition of 5.86%contains black carburization phase,which degrades the strength,hardness,and toughness of the c

关 键 词：超细晶硬质合金 WC-6Co 配碳量 微观组织 渗碳 脱碳 磁性能 力学性能 

分 类 号：TG135.5[一般工业技术—材料科学与工程]