Effects of Stirring Duration and Casting Temperature in Ultrasonic Assisted Stir Casting of Al A356 Matrix Composites

In the present study, two main parameters as stirring duration and casting temperature were taken into consideration in order to determine the effect of stirring process on mechanical properties of aluminum matrix composites. AlSi7Mg0.3 aluminum alloy and silicon carbide (SiC) particles were used as matrix and reinforcement materials to produce composite samples. Firstly, stirring processes were applied as the combination of mechanical stirring and ultrasonic vibration for the various time as 3-1, 2-2 and 1-3 minutes, respectively. To determine the effect of stirring process, tensile tests were applied to whole samples and Quality Indexes (QI) were calculated by using the results of tensile tests. According to the values of QI, the produced samples with the combination of 1 minute mechanical stirring and 3 minutes ultrasonic vibration showed the maximum mechanical properties. Afterwards, the determined stirring combination was chosen to specify the appropriate molten metal temperature. Three different casting temperatures were addressed as 700 degrees C, 720 degrees C and 740 degrees C. According to mechanical tests results and calculations of QI and metallographic analysis, the maximum mechanical properties were obtained with aluminum composite reinforced with 1 wt. % SiC at 720 degrees C molten metal temperature by applying 1 minute mechanical stirring and 3 minutes ultrasonic vibration.