Results and discussion Synthesis of in

Fig. 3indicates the optical micrographs of composite samples sintered at different temperatures of 500, 550 and 600 °C for different times of 1, 6 and 9 h. The defining characteristics of these composites include large voids, cracks and micro-sized porosities. As it is shown by the complementary empirical results in the present study, these defects are originated from the chemical reactions between AT and Al along the interfaces of these two phases. These interfacial reactions produce high-volume oxygen gas throughout the contact points of AT and Al and lead to their surface GDC-0994 [26]. Also, the longer sintering times or higher temperatures result in the greater volume fraction of microcracks and porosities. It implies that as the sintering time passes, the incomplete chemical reactions tend to terminate and increase the released gas volume thereby escalate the volume fraction of microcracks and porosities. This phenomenon is clearly observed in Fig. 4. As seen, aluminium titanate decomposes into its parent phases i.e. Al2O3 and anatase-TiO2 and forms aggregates between primary Al particles, thereby impeding the necking of Al particles during sintering. DSC analysis has verified that the formed anatase comes to a reaction with aluminium matrix in temperature range of 550–600 °C and produces in situ Al3Ti and O2 gas based on the following equations:equation(1)Al2TiO5→TiO2(rutile)+Al2O3Al2TiO5→TiO2(rutile)+Al2O3equation(2)TiO2-anatase+3Al→Al3Ti+O2TiO2-anatase+3Al→Al3Ti+O2