Synthesis of Iron Matrix Composite Reinforced by In Situ NbC Nanoparticulates

Abstract： In this work, taking the preparation of modi?er particles applied to iron-based alloys as research background, iron matrix composite reinforced by niobium carbide nanoparticulates was synthesized by ball milling niobium and graphite powder mixture to form Nb (C) supersaturated solid solution and then added iron powder continued milling to form a composite powder, subsequent heat treatment of the composite powder ensured the niobium carbide nanoparticulates precipitated in iron matrix. The structure evolutions and thermal properties of the milled powders were characterized by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC), the microstructure of the final product characterized by scanning electron microscope (SEM) and energy-dispersive spectrometry (EDS). The results reveal that the Nb (C) supersaturated solid solutions progressively formed after 6 h milling of Nb50C50 powder mixture. When heating the composite powder, NbC phase could form gradually as the temperature above 500℃, the transformation will be complete at 700℃. The SEM micrograph shows a self-organized dispersive system, which the NbC nanoparticulates are uniformly distributed in the iron matrix.