Magnesium alloys have an α-phase single-phase structure at the eutectic temperature, and have an α+β (Mg2Al3) structure at room temperature. Magnesium has a certain solubility in the α phase, and the atomic radius of magnesium is very different from that of aluminum, so it can produce a strong solid solution strengthening effect.
The α and β phases exist in the form of divorced eutectics. In the as-cast structure, the β phase appears in the form of a network at the grain boundary of the α phase, which will reduce the strength and plasticity of the alloy. Adopt solid solution and quenching treatment to eliminate β phase, which can improve its mechanical properties.
Magnesium alloys do not have aging strengthening effect and are not easy to carry out strengthening treatment. Although the solubility of magnesium in the α phase decreases with the decrease of temperature, since magnesium atoms are easy to diffuse and aggregate in aluminum, the natural aging process will occur even at room temperature, and the β phase will be precipitated. When the temperature is above 80°C, the aging process is faster, so it is not easy to use the heat treatment method of aging strengthening.