2016 年 57 巻 5 号 p. 600-607
Spark sintering behaviors of 10 vol% Fe added FeB powders with 10 μm size (here after called FeB-10Fe) were investigated in spark sintering process for the development of alternative materials of WC-Co alloys. Spark sintering behaviors of FeB-10Fe in the temperature range of 600 to 1493 K were the same in the sintering curves although their maximum temperatures changed from 1493 to 1523 K. The densification rates, Ḋ, of FeB-10Fe and pure Fe were also obtained experimentally, and the maximum point of Ḋ was shown at the D of approximately 0.75. The plastic deformation and power law creep deformation of Fe binder phase in FeB-10Fe compacts occurred before and after reaching maximum point of Ḋ, respectively. The sinterability was improved by 10 vol% Fe addition, and apparent relative density of FeB-10Fe compacts was increased with the increment of the sintering temperature of 1493 K to 1523 K. In contrast, the mean density of FeB-10Fe compacts was decreased with the increment of sintering temperature because of the poor wettability between liquid phase (Fe and Fe2B) and FeB phase in the liquid phase state at 1505 K and 1523 K. The values of Rockwell hardness of FeB-10Fe compacts were decreased with increment of sintering temperature because of the increment of porosities in FeB-10Fe compacts. In contrast, the values of micro hardness on the interfaces between grains were increased with increment of sintering temperature, because of the promotion of atomic diffusion between particles. There were maximum value of compressive-stress and -strain on compacts sintered at highest temperature, also because of promotion of the sintering in the interface between grains.
