The FeAl–30%TiC nanocomposite produced by mechanical alloying and hot-pressing consolidation

Abstract

Intermetallic matrix composites reinforced with particles such as TiC have attracted a great deal of attention over the past few years. In the present study, the mechanical alloying process followed by hot-pressing consolidation was used to produce FeAl–30%TiC nanocomposite. Since the reduction of grain size to the nanometer scale improves mechanical properties of materials, this composite may be attractive for structural applications. An elemental powder mixture of Al35Fe35Ti15C15 (in at.%) was milled in a high-energy ball mill. The phase transformations in the powder during milling were studied with the use of X-ray diffraction (XRD). Transmission electron microscopy and differential scanning calorimetry were used for examining the microstructure and the thermal stability of the milling product. The results obtained show that high-energy ball milling as performed in this work leads to the formation of a bcc phase identified as the Fe(Al) solid solution and a fcc phase identified as TiC, and that both phases are nanocrystalline. Subsequently, the milled powder was sintered at 750 °C under pressure of 4 GPa. The XRD investigations of the consolidated pellet revealed that after sintering, the material remained nanocrystalline and that there were no phase changes, except for the ordering of Fe(Al), i.e. formation of FeAl intermetallic compound, during the sintering process. The average hardness of the obtained nanocomposite is 1287 HV0.2 (12.6 GPa) and its density is 98% of the theoretical value.