火花等离子烧结制备超细晶WC-10Co-VC合金

Preparation of ultra-fine grain WC-10Co-VC alloy by spark plasma sintering

  • 摘要: 以自制超细VC粉为晶粒抑制剂,采用放电等离子烧结技术(SPS, Spark Plasma Sintering)成功制备了超硬WC-10Co-VC合金,并详细研究了VC含量对合金致密化程度、晶粒尺寸和力学性能的影响。结果表明,VC的加入降低了合金的相对密度,但抑制了晶粒长大。此外,随着VC含量的增加,合金的硬度和韧性都呈先增强后减弱的趋势。当VC添加量为3%时,在固溶强化和细晶强化的作用下,合金的硬度达到了最大值2 235 HV30。小尺寸晶粒不仅增加了裂纹偏转频率,而且延长了裂纹扩展路径,这增加了裂纹扩展的能量消耗,从而提高了合金的断裂韧性。

     

    Abstract: This work successfully prepared ultra-high hardness WC-10Co-VC cemented carbides by spark plasma sintering (SPS) with self-synthesized ultra-fine VC powder used as a grain growth inhibitor. The effects of VC content on the densification degree, grain size and mechanical properties were investigated. The results showed that adding VC decreased the relative density and inhibited grain growth. In addition, with the increase of VC content, both hardness and toughness increased first and then decreased. When the content of VC was 3%, the hardness reached the maximum value of 2 235 HV30 due to solid solution and fine grain strengthening. The small-sized grains not only increased the crack deflection frequency but also prolonged the crack propagation path, which increased the energy consumption of crack propagation, thereby improving the fracture toughness.

     

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