碳化帆颗粒尺寸对纳米晶硬质合金组织和性能的影响

Effect of VC Particle Size on Microstructure and Mechanical Properties of Nanocrystalline WC-Co Alloy

利用原位还原碳化反应制备纳米尺度的WC-Co复合粉体,应用放电等离子烧结(SPS)技术制备出纳米晶WC-Co硬质合金块体材料。分析了晶粒长大抑制剂碳化钒(VC)颗粒尺寸对纳米晶硬质合金的显微组织、晶粒尺寸及分布和力学性能的影响。结果表明:当VC的粒径减小到100 nm以下时,利用快速烧结技术可制备得到平均晶粒尺寸约为70 nm的致密WC-Co硬质合金块体材料,其物相纯净,晶粒尺寸分布均匀,维氏硬度为19.84 GPa,断裂韧性达到12.10 MPa·m1/2。

The in-situ reduction and carbonization reactions were used to synthesize the WC-Co composite powder with nanoscale particlesizes. The nanocrystalline WC-Co cemented carbides bulk material was prepared by spark plasma sintering （SPS）. Results show that theparticle size of the grain growth inhibitor VC has a significant effect on the microstructure, grain size and properties of the preparednanocrystalline WC-Co bulk material. When the VC particle size is below 100 nm, the prepared nanocrystalline WC-Co bulk has a meangrain size of about 70 nm. It has a high density, pure phase constitution, homogeneous grain size distribution and excellent mechanicalproperties, with a Vickers hardness of 19.84 GPa and a fracture toughness of 12.10 MPa·m1/2