SYNTHESIS OF NIAL-TIC NANOCOMPOSITE BY MECHANICAL ALLOYING ELEMENTAL POWDERS

A NiAl-TiC nanocomposite has been synthesized by mechanical alloying f rom Ni, Al, Ti, and C powders. During milling, an abrupt reaction occu rred, resulting in simultaneous formation of NiAl and TIC phases. It i s suggested that two separate exothermic explosive reactions, i.e, Ni + Al --> NiAl and Ti + C --> TiC, were involved. However, the reaction s were incomplete with the existence of a small amount of elemental po wders. Prolonged milling led to a gradual formation of NiAl and TiC as well as grain refinement. The final grain size for TiC was 3.5 times as large as that for NiAl. The formation mechanism of the NiAl-TiC nan ocomposite during mechanical alloying was also discussed. (C) 1998 Els evier Science S.A. All rights reserved.