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以超细WC粉末和超细WC-6Co复合粉末为原料,添加VC/Cr3C2作为晶粒长大抑制剂,同时进行配碳,采用高能球磨和气压强化烧结制备晶粒度小于0.5μm的WC-0.5Co超细硬质合金,研究了不同VC/Cr3C2添加量及配碳量对其组织与性能的影响。结果表明:VC/Cr3C2有效抑制了烧结过程中WC晶粒的长大,显著提高了WC-0.5Co超细硬质合金的硬度。当VC/Cr3C2添加量为0.73%(质量分数,下同)时,合金的硬度(HV0.05)最高,达到32 658 MPa;同时一定的配碳量有利于控制合金中的脱碳,提高合金性能,当配碳量为0.2%时,WC-0.5Co-0.73VC/Cr3C2合金的综合力学性能最好,断裂韧性为6.935 MPa·m1/2,维氏硬度(HV0.05)为32 216 MPa。
The ultrafine WC powder and ultrafine WC-6Co composite powder were used as raw materials, VC / Cr3C2 was added as grain growth inhibitor, and carbon was mixed at the same time. High-energy ball milling and pressure-enhanced sintering were used to prepare WC- 0.5Co ultrafine cemented carbide. The effects of different amounts of VC / Cr3C2 and carbon content on the microstructure and properties were studied. The results show that VC / Cr3C2 effectively inhibits the growth of WC grains during sintering and significantly increases the hardness of WC-0.5Co ultra-fine cemented carbide. When the amount of VC / Cr3C2 is 0.73% (mass fraction, the same below), the hardness of the alloy (HV0.05) is the highest, reaching 32 658 MPa. At the same time, a certain amount of carbon content is helpful to control the decarburization in the alloy and improve the alloy The mechanical properties of WC-0.5Co-0.73VC / Cr3C2 alloy are the best when the carbon content is 0.2%, the fracture toughness is 6.935 MPa · m1 / 2 and the Vickers hardness (HV0.05) is 32 216 MPa .