VC/Cr3C2及配碳量对WC-0.5Co超细硬质合金组织与性能的影响

Influence of VC/Cr3C2 and Mixed Carbon Content on Microstructure and Properties of Ultrafine WC-0.5Co Cemented Carbide

摘要:

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0.5 μm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

Abstract:

The ultrafine WC-0.5Co cemented carbide with a grain size smaller than 0.5 μm was prepared by high energy ball milling and HIP-sintering process. The raw materials were ultrafine WC and WC-0.5Co powder and the additives of grain growth inhibitor were VC/Cr3C2 and carbon. Microstructure and properties of the ultrafine WC-0.5Co cemented carbide with different VC/Cr3C2 and carbon contents were studied. The results show that there is a significant effect of VC/Cr3C2 on controlling WC particle size and hardness of ultrafine WC-0.5Co cemented carbide. Ultrafine WC-0.5Co cemented carbide has best Vickers hardness HV0.05 of 32 658 MPa with the VC/Cr3C2 content of 0.73% (mass fraction, similarly hereinafter). A certain amount of mixed carbon content is good for decarburization and properties of the ultrafine binderless cemented carbide. Ultrafine WC-0.5Co-073VC/Cr3C2 cemented carbide has best comprehensive mechanical properties with transverse rupture strength of 6.935 MPa·m1/2 and Vickers hardness HV0.05 of 32 216 MPa when the mixed content of carbon is 0.2%