in situ Fabrication of Fe-TiB2 Nanocomposite Powder by Planetary Ball Milling and Subsequent Heat-treatment of FeB and TiH2 Powder Mixture

Abstract

Fe-TiB2 powder was synthesized in-situ by the planetary ball milling and subsequent heat-treatment of an iron boride (FeB) and titanium hydride (TiH2) powder mixture. Mechanical activation of the (FeB+TiH2) powder mixtures was observed after a milling time of 3 hours at 700 rpm of rotation speed, but activation was not the same after 1 hour milling time. The particle size of the (FeB+ TiH2) powder mixture was reduced to the nanometer scale, and each constituent was homogeneously distributed. A sharp exothermic peak was observed at a lower temperature (749 ℃) on the DSC curves for the (FeB+TiH2) powder mixture milled for 3 hours, compared to the one milled for 1 hour (774 ℃). These peaks were confirmed to have resulted from the formation reaction of the TiB2 phase, from Ti and B elements in the FeB. The Fe-TiB2 composite powder fabricated in situ exhibited only two phases of Fe and TiB2 with homogeneous distribution. The size of the TiB2 particulates in the Fe matrix was less than 5 nm.