Microstructures and Mechanical Properties of an Al-Cu-Li-Mg-Zr Alloy Containing Zn and Mn
An Al-3.43Cu-1.28Li-0.49Mg-0.12Zr containing 0.62Zn and 0.29Mn was designed and the microstructures and mechanical properties of the alloy with various heat treatments were investigated. The precipitates of the alloy consist of T1 (Al2CuLi), θ′ (Al2Cu) σ (Al5Cu6Mg2) and δ′ (Al3Li). As solution temperature is changed from 485°C to 530°C, the solution degree of alloying elements in alloy increased, the amount of T1 in the alloy aged at 160°C for 18 h increased and that of θ′ is decreased, resulting in an increase of strength. After solution treatment at 530°C, the alloy aged for 18 h at 145°C is mainly strengthened by G P zones, and a little amount of T1 precipitates. As aging temperature is increased to 160°C and 175°C, the strength increased, due to the sufficient precipitation of σ and T1. The smaller amount of T1 in the alloy aged at 190°C is consistent with its lower strength. Meanwhile, it is found that the σ precipitate does not coarsen as aging temperature increases in the range from 160°C to 190°C.
Yafang Han et al.
Y. L. Chen et al., "Microstructures and Mechanical Properties of an Al-Cu-Li-Mg-Zr Alloy Containing Zn and Mn", Materials Science Forum, Vols. 546-549, pp. 995-1002, 2007