In situ dual matrix composite with segregated microstructure fabricated from Al–TiO2–B2O3 system by mechanical thermal process

Abstract

Three different in-situ Aluminum matrix composites (AMCs) were synthesized by mechanical thermal process via powder metallurgy route from Al–B2O3–TiO2 system, where the B2O3/TiO2 mole ratios were taken as 0, 0.5 and 1. The results show that the composite with B2O3/TiO2 mole ratio of 1 exhibits the best mechanical properties among all the composites. Therefore, the mole ratio of 1 was used to synthesize the Alc/(Alf–Al2O3–TiB2) dual matrix composite with segregated microstructure. This composite consists of two regions, namely reinforcement rich area (Alf–Al2O3–TiB2, where f stand for fine) and reinforcement lean area (Alc, where c stands for coarse), which form a bicontinuous microstructure giving a good combination of strength and ductility. For comparison, Alf–Al2O3–TiB2 single matrix composite with an equivalent content of uniformly distributed reinforcement was also fabricated. The composites were characterized using DSC, XRD, SEM and TEM. The compression testing was conducted with a strain rate of 10−4 at RT, 150 and 450 °C. The ductility and wear resistance of Alc/(Alf–Al2O3–TiB2) dual matrix composite improved in comparison to the Alf–Al2O3–TiB2 single matrix composite due to its segregated bicontinuous dual matrix microstructure.