Anisotropy of mechanical properties of 2297-T87 Al–Li alloy thick plates

Abstract

The tensile properties of 2297-T87 Al–Li alloy thick plates at different thickness position and in different direction were analyzed via tensile testing, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and transmission electron microscopy (TEM). Results indicated that the ultimate tensile strength (UTS) and yield strength (YS) of the alloy decreased firstly and then increased from the 1/8T position to the 1/2T position, whereas elongation to failure (E_f) decreased gradually such that its value along the rolling direction (RD) was higher than those along the transverse direction (TD) at the same thickness position. From the 1/8T position to the 3/8T position of the alloy, the UTS and YS along the TD were higher than those along the RD. At the 1/2T position of the alloy, the UTS, YS, and E_f along the RD were the highest, whereas those along the normal direction (ND) were the lowest. Microstructural observations further revealed that the anisotropy of tensile properties was related to grain morphology, crystal texture, second-phase particles, and Li atom segregation.