Effect of re-sintering temperature on compact microstructure and compressive properties of SiC and Ti reinforced aluminum matrix composites by powder metallurgy

SiC and Ti reinforced aluminum matrix composites (AMCs) were fabricated by powder metallurgy, which were sintered at different re-sintering temperatures to improve their compressive property. The microstructure, phases, and nanohardness of obtained AMCs were analyzed using an optical microscope (OM), X-ray diffraction (XRD), and nano indenter, respectively. The effect of re-sintering temperature on the compressive property of SiC and Ti reinforced AMC was measured using an electronic universal machine, and the fracture morphologies and chemical compositions were investigated using a scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), respectively. The results show that the grains on the SiC and Ti reinforced AMCs become finer and slender with the increase of re-sintering temperature in the range of 700-750 degrees C, which further strengthen their mechanical property. The density and contribution of dislocation are also improved with the increase of re-sintering temperature. The elevated re-sintering temperature improves the dispersive distribution of reinforcements and decreases the porosity, which increases the nanohardness and elastic modulus of SiC and Ti reinforced AMCs. The compressive strength of SiC and Ti reinforced AMCs re-sintered at 750 C-o is superior to that re-sintered at 700 degrees C due to the combination of fine grain and dislocation strengthening.