Microstructeral characterization and mechanical properties of nonostructured Al2024 alloy and Al2024 based composites

In this research, mechanical alloying was used to synthesize ultrafine grained AA2024 and AA2024-B4C powders in an attrition mill under argon atmosphere up to 50 h with the rotational speed of 400 rpm. In order to determine the grain size of the matrix, X-Ray diffraction test and Williamson–Hall method was used. After mechanical alloying, hot pressing and hot extrusion were used for densification of powders. The microstructure and mechanical behavior of hot extruded samples were characterized by scanning electron microscopy (SEM), tension and compression and hardness tests. The microstructure of samples showed that the CuMgAl2 precipitate is present. Furthermore, the distribution of these precipitates in nanostructured samples was more uniform and their content was greater. The results of mechanical tests indicated that the strength and hardness of AA2024 alloy after mechanical alloying and addition of B4C particles increases for 64 and 49%, respectively. In other words, the AA2024-B4C nanocomposite showed the highest strength and hardness, however, its elongation was the lowest.