烧结温度对BN/Ni(Cr)自润滑材料组织与性能的影响

摘要

以Ni-20％Cr(质量分数)合金粉末作为基体材料,添加体积分数为31.4％的六方BN(h-BN)作为固体润滑剂,采用粉末冶金法制备BN/Ni(Cr)自润滑复合材料.研究不同烧结温度对该复合材料硬度、弯曲强度和孔隙率以及显微组织的影响.研究结果表明:BN/Ni(Cr)自润滑材料的硬度和抗弯强度与Ni-Cr颗粒烧结颈的形成、长大以及孔隙率的变化有关；当烧结温度不超过1 180℃时,随着温度的升高,BN/Ni(Cr)复合材料的孔隙率下降,硬度和弯曲强度均呈上升趋势.%BN/Ni(Cr) self-lubricating composites were fabricated by powder metallurgy, where the Ni-Cr solid solution powder was used as matrix material, with a hexagonal BN(h-BN) powder added as solid lubricant. Effects of sintering temperature on the density, porosity, hardness and three-point bending strength were studied. Meanwhile, the microstructural evolution of BN/Ni(Cr) composites was observed. It is found that the hardness and three-point bending strength of BN/Ni(Cr) self-lubricating composites are related to the formation, growth of the sintered necks and variance of the porosity. Besides, when the temperature is no higher than 1 180 °C, the porosity of BN/Ni(Cr) composites decreases with the increase of temperature, while the hardness and three-point bending strength of them increase.