Synthesis of particulate in situ Aluminium-Alumina composite by using aluminothermic reactions

Particle reinforced metal matrix composites (MMCs) are an important class of composite materials. During last decades, particulate metal matrix composites have found special industrial applications in producing wear-resistance components. One of the best ways for producing cast particulate composites is In-Situ methods. The advantage is considered to be of higher compatibility and improved particle matrix interfaces. A commonly adopted in situ method involves reaction between a metal oxide and aluminium to produce alumina particles or whisker reinforcements. By completing the alumina formation reaction, the reduced metal usually further reacts with Al to form intermetallic phases, which also act as reinforcements in the matrix of the composite. Because of the formation of ultrafine and stable ceramic reinforcements, the in situ MMCs are found to exhibit excellent mechanical properties. In this study, In-situ particlereinforced aluminium based cast composites have been synthesized by dispersion of externally added Zinc Oxide particles into molten aluminium at different processing temperatures. Alumina particles (Al2O3) form through chemical reaction of ZnO particles with molten aluminium. Simultaneously, the chemical reaction also releases Zinc, which dissolves into molten aluminium during solidification. X-ray diffraction and scanning electron microscopy have been used to study the various reaction mechanisms and transformations.

Keywords:

metal matrix composites , particulate , in-situ , zinc oxide , alumina particle