The Effect of Milling Time on Mechanical Properties of Al - Al2O3 Ex-Situ Cast Composite

In this research, aluminum powder and alumina were milled in a high-energy planetary mill at different times to manufacture capsules of powdery composites (Al-Al2O3)CP. Then, these capsules were added to aluminum melt and cast through ex-situ. Scanning electron microscope was used to study the morphology of the capsules and the microstructure of the cast composites. The percentage of capsules and reinforcement particles in cast composite were measured by utilizing Image Tool software. By optimizing the milling time to 5 hours, the percentage of the reinforcing particles in the cast composite matrix increased dramatically; moreover, the weight of the sample in the wear test was significantly reduced and the wear mechanism shifted from adhesive to abrasive.