Nanocomposites obtained by mechanical alloying in Fe-Al-Ti-C system

We investigated the reactive milling process in the Fe-Al-Ti-C system. The composite powders with Fe(Al) solid solution matrix reinforced by 50%, 30% and 10% of TiC carbide, depending on the Ti and C content in the starting powder mixture, were produced throughout this process. In the case of the process which yielded composite containing 50% of TiC, abruptly, in the first step of milling, a significant amount of TiC carbide and of partially ordered Fe(Al) solid solution has been formed. In two other cases the first stage of the milling brought about formation of disordered Fe(Al) solid solution, while TiC was developed later. The final products of performed milling processes were nanocrystalline, with the estimated mean crystallite size in the range of 8-15 nm and of about 18 nm for Fe(Al) and TiC, respectively. Heating of the produced powders in the calorimeter up to 720 degrees C caused ordering of the Fe(Al) solid solution and its transformation into an FeAl intermetallic. Limited growth of grains up to about 20 nm as well as a decrease of the mean lattice strain also took place during heating. (c) 2007 Elsevier B.V. All rights reserved.