Microstructural Features and Mechanical Properties of Artificially Aged AA2024

Microstructural features and mechanical properties of Al–Cu–Mg alloy (AA2024) were examined after aging the alloy between 105–195°C for various durations. One set of the specimens was aged at 105, 135, 165, and 195°C for 2 h, whereas the aging of other set of specimens at these temperatures was performed for 3.5, 3, 2.5, and 2 h, respectively. X-ray diffraction and scanning electron microscopy results indicated the formation of S- (Al2CuMg) and Θ- (Al2Cu) phase precipitates whose density and size changed with aging time and the temperatures. Anomalous variations in yield strength, ultimate tensile strength, plastic elongation, elastic modulus and hardness were observed with either changing the aging temperature, or the time. However, the specimens aged at 135 and 195°C for 2 h displayed the maximum strength and hardness along with a slight decrease in their plasticity as compared to those aged at other temperatures with various durations.