FABRICATION OF NiA MATRX HYBRDULTRAFINE COMPOSITE FROM THE Ni-Al-Ti-BC SYSTEM VILA COMBUSTION SYNTHESIS

In this article preparation of NiAl matrix hybrid ultrafine composite with up to 40%wt TiC-TiB2 as reinforcement was achieved by thermal explosion mode of combustion synthesis from the Ni-Al-TiB4C system. BC powder was used as a source of both B and C, which is much greatly reduced the fabrication costs. Scanning electron microscopy (SEM) and wavelength dispersive spectroscopy (WDS) were used to characterize the microstructure of the synthesized composites and elementalmap distribution respectively. X-ray diffraction was used to investigate the phases of the final products. It was revealed that products contained NiAl, TiB, and TiC compounds with the small amount of B13C2 and Ti. It was illustrated that existence of B13C, may have been due to the coarse size of BC in starting material which restricted diffusion of B and C. The adiabatic temperature, particle size of reinforcements, and amount of remained B13C2 increased with increasing in theamount of reinforcement. Particles size of reinforcement was in the ultrafine range for lower amount of reinforcement. However, increasing the amount of reinforcement leads to increasing the particle size to micron range.

Keywords:

combustion synthesis , SHS , NiAl , TiB2 , hybrid composite