An investigation into fabrication and characterization of direct reaction synthesized Al-7079-TiC in situ metal matrix composites

The present study was attempted to highlight a novel direct reaction synthesis in which traditional casting plus rapid solidification techniques were implemented to produce Al-7079-TiC in situ composites with homogenous microstructure and improved dispersion strengthening by the reinforcing phases. Casted samples were effectively characterized by scanning electron microscopy followed by energy dispersive spectroscopy and X-ray diffraction. Ingot metallurgy showed a homogenous distribution of TiC particles inside the grain. This particle behavior acted as an excellent nucleation sites for the Al dendrites to grow unvaryingly. TiC reinforcements have semi coherent relationship with alpha-Al matrix. It was observed that eutectic boundary includes the second phases based on eta(MgZn2) and Mg (Zn, Cu, Al)(2). Almost 90% of the in situ reinforced TiC were homogenously distributed along the center of the grain. Thermal history conditions have shown an exothermic behavior during casting. Experimental results revealed the evolution of TiC particles in super-heated melt region, i.e. dissolution of titanium continued by reaction of titanium with diffused carbon in the Al matrix to form TiC particles. Further they acted as nucleation sites for the alpha-Al dendrites to grow homogenously. This study presents optimum process temperature for the Al-TiC in situ synthesis. (c) 2018 Politechnika Wroclawska. Published by Elsevier B.V. All rights reserved.