镍含量对超细WC-Ni-VC-TaC硬质合金结构和力学性能的影响

Influence of Ni Content on the Structure and Mechanical Properties of Ultrafine WC-Ni-VC-TaC Hardmetals

采用放电等离子烧结(SPS)方法,结合使用VC和TaC晶粒抑制剂,制备Ni质量分数为6%~10%的超细WC-Ni硬质合金。研究表明,所制备WC-Ni-VC-TaC硬质合金WC晶粒在0.2~0.4μm;合金中含有大量微孔,但微孔大小随合金中粘结相Ni含量增加而减小。且随合金中Ni含量增加,合金中WC晶粒略有增长,合金相对密度先减小后增大,硬度由24500MPa逐渐减小到18600MPa(HV1),但抗弯强度却由1600MPa增大到2140MPa。

A series of ultrafine WC-Ni hardmetals with different fractions of nickel metal binder from 6-10 wt% were fabricated by sparking plasma sintering with the assistance of VC and TaC as inhibitors of WC grain growth. The results indicate that the WC grain size of the as-prepared WC-Ni-VC-TaC hardmetals is in the range of 0.2-0.4 μm; there are lots of micro-pores in the materials, and their sizes are decreased with increasing content of Ni in the hardmetals. With the increase of Ni content in the hardmetals, the relative density of the as-prepared hardmetals is decreased first and then increased, and their hardness is decreased from 24500 MPa to 18600 MPa (HV1), but the flexural strength is increased from 1600 MPa to 2140 MPa.