A Comparative Study on the Microstructure and Mechanical Properties of Al-Si-Cu/1wt %NCP Composites after T6 Heat Treatment

In this article, microstructural characteristics and mechanical properties of Al-Si-Cu/NCP composites were evaluated. Reinforced nanocomposites with 1 wt% nano-clay were fabricated by the method of the stir casting. Stirring times and temperatures were variable parameters to produce specimens. Consequently, the effect of a T6 heat treatment, which contained solutioning at 490 ºC for 5 hrs, quenching, and aging process at 200ºC for 2 hrs, on tribological behavior and compression properties of nanocomposites was inspected. The microstructural observation was conducted by optical microscopy (OM) and the field emission scanning electron microscopy (FESEM). The acquired results demonstrated that nano-clay particles were distributed in the aluminum matrix. The range of Vickers hardness values was 123 to 158 VHN for nanocomposites. The wear resistance of nanocomposites enhanced when the stirring time and temperature increased to 4 mins and 800 ºC, respectively.  The best compressive mechanical properties correlated to the nanocomposite fabricated at 750 ºC and stirred for 2 mins.  The higher stirring time and temperature resulted in the formation of AlSiFe intermetallic phase which reduced the ultimate compressive strength.