Cr、V、RE添加剂对特粗晶与超粗晶硬质合金微观组织与性能的影响

Effects of Cr,V and RE additives on microstructures and properties of super extra coarse and extra coarse cemented carbides

利用特粗晶与超粗晶硬质合金粗大粘结相平均自由程以及粗大WC原料粉末的特性,研究单一Cr、V以及Cr-RE与V-RE添加剂对特粗晶与超粗晶WC-Co合金微观组织结构、物理力学性能以及合金中Co粘结相纳米压痕力学性能的影响。结果表明,在此合金体系,Cr的加入可使合金保持微观组织结构均匀、WC晶粒粗大以及高韧性的特性,而且可使Co粘结相纳米压痕硬度HV2 mN提升了20.5%;V的加入使合金中WC晶粒大小出现明显两极分化,并显著降低合金韧性;微量混合稀土(RE)对V和Cr在合金中的作用行为影响不显著;合金矫顽磁力、硬度以及Co粘结相弹性模量对合金成分变化不敏感。

Taking the advantage of the large mean free path of the binder phase and the coarse WC raw material, the behaviors of Cr, V, Cr-RE and V-RE additives in super extra coarse and extra coarse WC-Co alloys were investigated. It included the microstructure, physical and mechanical properties of the alloys and the nano indentation mechanical properties of the cobalt binder phase. The results show that in these alloy systems, the alloys with Cr additive are characterized with homogeneous microstructure, super extra coarse WC grain size and high toughness. With the independent addition of Cr, the nano indentation hardness HV2mN of the cobalt binder phase of the alloy can be increased by 20.5%. The addition of V can result in the polarization of the WC grain sizes and the substantial decrease in toughness The effect of RE （mischmetal） in small amount on the behavior of Cr, V in the alloys is insignificant. The magnetic coercivity and hardness of the alloys as well as the elastic modulus of the cobalt binders are insensitive to the composition of the alloys.