Solid state reactions in Ni-Al-Ti-C system by mechanical alloying

Several Ni-Al-Ti-C compositions from different areas of the Ni-Al phase dia gram containing various amounts of Ti and C were prepared by mechanical all oying. Synthesized samples were investigated by X-ray diffraction and diffe rential scanning calorimetry methods. Solid state reactions in Ni-Al-Ti-C p owder mixtures with an equiatomic Ni/Al ratio lead to the formation of NiAl and TiC equilibrium phases. Metastable solid solution of Ni(Al,Ti,C) and n on-stoichiometric TiCx are formed in the mixtures with C-Ni/C-Al ratio of 1 .7-3. The grain size of metastable intermetallic phases is less than 5 nm, if Ni and Al content in the mixtures corresponds to the dual-phase and Ni,A l-areas of the Ni-Al phase diagram. (C) 2000 Elsevier Science S.A. All righ ts reserved.