Al-4 wt% Cu composite reinforced with in-situ TiB2 particles

Al-4 wt% Cu/TiB2 metal matrix composite has been fabricated with an exothermic reaction process at 850 degrees C via K2TiF6 and KBF4 salts. Microstructural observation revealed the hexagonal shape of the in-situ TiB2 particles after a reaction holding time of 5 min. Although the exothermic reaction became more nearly complete with the increase in reaction time, the size of the in-situ TiB2 particles was less dependent on reaction time. Microstructural observation showed that the grain size of the composite was refined dramatically at the beginning of the reaction. However, it increased slightly al the later stage of the reaction. Because of the change in the volume of TiB2 and grain site, the yield and ultimate tensile stresses of the composite increased with reaction durations. Fractographs of the in-situ metal matrix composite showed ductile fracture mode. (C) 1997 Acta Metallurgica Inc.