Work

Effect of homogenization heat treatment on microstructure evolution and mechanical properties of Mg–8Li–3Al–1Y-0.5Gd alloy

Year: 2026

Type: article

Abstract: Homogenization heat treatment process has been widely applied in the processing of alloy materials because it can eliminate casting segregation, improve alloy properties and affect subsequent plastic processing. In this paper, the effect of homogenization heat treatment on both the microstructure evolution and mechanical properties of as-cast Mg-8Li-3Al-1Y-0.5Gd alloy were studied. The results show that the phase composition of the alloy after homogenization treatment is not changed, which is mainly composed of α-Mg phase, β-Li phase, AlLi phase and Al2(Y, Gd) phase. As the homogenization temperature increased, the loss of lithium became significant at 350 °C, and the hardness of the alloy decreased at this temperature. Therefore, 300 °C was determined as the temperature for subsequent homogenization treatment. With the increase of the homogenization time, the AlLi phase was dissolved, the Al2(Y,Gd) phase was uniformly distributed, and the needle-like a-Mg phase was precipitated. The texture strength of α-Mg phase decreases first and then increases. The best tensile strength (296 ± 11 MPa) and yield strength (256 ± 8 MPa) were obtained when the homogenization time was 4 h. The strengthening mechanism originated from the synergistic effect of solid solution strengthening of the AlLi phase and grain boundary strengthening of the α-Mg phase. The fracture morphology was investigated and it was found that the fracture mode of this alloy was quasi-cleavage fracture. Additionally, this study explores the optimal homogenization heat treatment process of this alloy system, which provides a basis for subsequent plasticity processing homogenization treatment.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2026.03.263