烧结温度对Mo2FeB2合金组织性能的影响

Effect of sintering temperature on the structure and properties of ternary boride hard alloys

采用真空液相烧结法制备三元硼化物硬质合金，研究了烧结温度对三元硼化物硬质合金致密度、显微组织以及物相组成的影响。研究结果表明，三元硼化物硬质合金的密度和显微组织与烧结温度密切相关。当烧结温度较低时，合金中的硬质相晶粒发育不完全，且在粘结相中分布不均匀；烧结温度过高时，合金中的硬质相颗粒粗大，两者都会显著影响材料的性能。试样在1160～1210℃之间烧结时，随着烧结温度的不断增加，材料由固相烧结逐渐转化为液相烧结，试样的密度随着烧结温度的上升而逐渐增加，并确定试验最佳烧结温度为1210℃，此时材料的密度为8．23g／cm^3，维氏硬度与洛氏硬度分别为8722．6N／mm^2和75．3HRA，抗弯强度则达到1246．38MPa。通过对材料的显微组织与物相结构分析，阐述了该材料组织结构变化的原因。

Ternary boride hard alloy was prepared by vacuum liquid phase sintering technique. The effects of sintering temperature on density, microstructure and phase composition of the hard alloy were studied. The results show that the density and microstructure of ternary boride are closely related with sintering temperature. The hard phase crystal is ateliotic and non-uniform in the binder phase at lower sintering temperature, but the hard phase crystal is coarsened at h higher sintering temperature. When the material is sintered at 1160-1210℃ , the sintering mechanism changes from solid-phase sintering to liquid-phase sintering gradually and the studied material＇s sintering density increased with increasing of the sintering temperature. The optimal sintering temperature is 1210℃ and at this temperature, the density of the ternary boride is 8.23g/cm^3. The vickers hardness and rockwell hardness are 8722.6N/mm^2 and 75.3HRA, and the bending strength is 1246.38MPa. The reason of structure change is expounded via analysis on microstructure and phase composition.