Investigation of stress effect on creep, precipitation and dislocation evolution of Al–Li alloy during creep age forming

The 3rd generation Al–Li alloy is a good candidate for large panel fabrication adopting creep age forming (CAF) because of its balanced synergy high strength, toughness, corrosion resistance and light weight. In this study, the creep-ageing behaviour 2xxx series in T8 state has been experimentally investigated under different stresses ranging from 300 to 430 MPa at 143 °C up 20 h. corresponding evolution precipitate size, distribution dislocation density during CAF analysed using transmission electron microscopy (TEM) X-ray diffraction (XRD) tests. With increase applied stress, dominant deformation mechanism transformed diffusion around 400 MPa, with stress exponent n = 2.9 former 8.4 latter. A strong dependent characteristic observed evolutions size creep-ageing. strain increased dramatically above accumulated was 7 times higher than that after h Much according XRD measurements, which accelerates precipitation kinetics. It also found dominance T1 over θ′ precipitates ageing time °C.