Al–Mg–Li alloy was prepared using powder metallurgy and hot extrusion methods. The microstructure

fracture morphology and mechanical properties of the alloy were analyzed using metallographic microscopy

scanning electron microscopy

transmission electron microscopy

and a tensile testing machine. The effects of different Mg/Li ratios (1.3

1.8

2.5) on the microstructure and mechanical properties of the alloy in the sintered

extruded

and T6 heat-treated states were investigated. The results revealed that an increase in the Mg/Li ratio led to an increase in the relative density of the sintered alloy

indicating the promoting effect of Mg on the sintering process. For the extruded Al–Mg–Li alloy

as the Mg/Li ratio increased

the precipitation of Mg-containing phases gradually increased and clustered near the grain boundaries

resulting in improved mechanical properties

the tensile strength of which increased from 285 MPa to 407 MPa. After T6 heat treatment

the second phase in the Al–Mg–Li alloy mainly consisted of δ′ phase and T phase. The δ′ phase

as the main strengthening phase

was uniformly distributed in the aluminum matrix

while the T phase exhibited a chain-like distribution along the grain boundaries. Increasing the Mg/Li ratio enhanced the tensile strength and yield strength of the alloy

but it may lead to a decrease in elongation. For instance

the Al–5Mg–2Li alloy after T6 heat treatment exhibited a tensile strength of 532 MPa

a yield strength of 473 MPa

and an elongation of 4.5%.