Structural and morphological study of a 2024 Al-Al2O3 composite produced by mechanical alloying in high energy mill

Materials and Design 37 (2012) 96-101, 2011.


2024 Al composite reinforced with Al2O3 particles was obtained by mechanical alloying (MA) using Al, Cu and Mg elemental powders as raw materials and Al2O3 nanoparticles as reinforcement. The results shown that as the MA time increased, the non-reinforced (WR) and Al2O3 reinforced powders (R1A and R2A) morphology changed from flake-flattened to equiaxed. Regarding the average particle size, WR group displayed a continuous decreasing value even for a processing time of 10 h while R2A and R1A groups shown a constant value for the same time. This led to the conclusion that steady state of the process was reached in shorter times in presence of Al2O3 nanoparticles. It was found that the reinforcement was present in the matrix like isolated particles and small agglomerates which affected the dislocation motion, and it was assumed that this fact caused the increase observed in the microhardness values. There was no evidence of new phase precipitation through MA process.