Investigation of Reaction Mechanism, Structure and Mechanical Properties of the In-situ Composites Fabricated in Al-V2O5-NiO System

In this study, fabrication of an in-situ composite through aluminothermic combustion synthesis in An Al–V2O5-NiO system was investigated. Therefore, Al, V2O5 and NiO powders with stoichiometric ratio of 11:1:1, respectively, were milled for an hour and finally the mixtures were compressed. In order to investigate the temperatures of phase transformations, Differential Thermal Analysis (DTA) was utilized. Heat treatment was applied on the raw samples according to their peak temperatures treated in DTA. X Ray Diffraction (XRD) analysis for the samples shows formation of phases such as Al3V and Al3Ni2 at different sintering temperatures. Microstructure and phase analysis showed that during sintering of this sample, Al3V phase was not formed below 700 °C, at 880 °C Al3Ni2 it was formed and after 950 °C, it was transformed to Al4Ni3 phase. In addition, after 950°C, Al3V transformed into Al23V4 phase. Analysis of samples density and hardness showed that, due to increase of volume fraction percentages of reinforcing phase, these two parameters increase as well.