Effect of Milling Time and Process Control Agent on Microstructure and Mechanical Properties of AA2024-2 wt.% Cu Metal-Metal Composites Produced by Mechanical Alloying

It is possible to avoid problems such as the decrease in toughness and ductility caused by ceramic reinforcements in ceramic reinforced metal matrix composites by using metal as reinforcement instead of ceramic. In this study, the effects of process control agents and milling time on the mechanical properties of 2 wt.% Cu-reinforced AA2024 composites produced by mechanical alloying and hot pressing were investigated. For this purpose, 2 wt.% methanol and stearic acid were chosen as process control agents, and 2, 4, 6, and 8 h were selected as milling time. Then, the composite powders were hot-pressed at 560 degrees C and 500 MPa. Particle size, morphology, and microhardness of the milled powders and the density, porosity, hardness, tensile strength, and microstructure of the composites were investigated. With an increase in milling time and process control agents, the improvement in the mechanical properties of the composites was more effective in methanol than in stearic acid. After 8 h milling with methanol agent, a 22% increase in hardness and 19% increase in tensile strength were achieved compared to 2 h milling.