The growing demand for lightweight materials in the automotive and aerospace industries underscores the importance of investigating new magnesium (Mg) alloys for their application in these sectors. The unique characteristics of Mg alloys, such as their high strength-to-weight ratio, dimensional stability, and recyclability, make them ideal candidates for weight reduction in vehicles. However, the hexagonal close-packed crystal structure provides only a limited number of slip systems and generates distinct deformation textures characterized by significant mechanical anisotropy and tension-compression yield asymmetry, which can affect their performance under dynamic loads.

Despite the extensive investigations into fatigue behavior conducted on other series of Mg alloys, such as magnesium-aluminum-zinc (Mg-Al-Zn) and magnesium-aluminum-manganese (Mg-Al-Mn), there remains a notable absence of studies on Mg-Zn alloys modified with rare earths and their response to cyclic stresses. It has been observed that the integration of rare earths in these alloys during the extrusion process can notably enhance their fatigue properties by generating uniform microstructures with weaker textures. However, further research is required to gain a deeper understanding of how these alloys behave under cyclic stresses.

The study aims to investigate the microstructural and fatigue properties in air of extruded Mg-Zn alloys (Mg-2Zn, Mg-1Zn) with varying contents of yttrium (Y) and calcium (Ca). The alloys were extruded at a temperature of 350 °C, with an extrusion speed of 1 mm/s and an extrusion ratio of 1:25. Microstructural characterization of the extruded bars was conducted using SEM/EDS. Texture analysis were performed using EBSD to identify alloys with the weakest textures, which were selected for fatigue testing. Constant amplitude fatigue tests were carried out for a maximum number of cycles N_limit = 2∙10⁶ at a stress ratio of R = -1 (fully-reversed tension-compression loading). The alloys exhibited comparable results, with the highest fatigue strength of 95 MPa observed for Mg-1Zn-0.8Y. This enhancement is attributed to the grain refinement effect and the high solubility of yttrium in magnesium, which contribute to grain refinement and solid solution strengthening mechanisms. This study provides crucial information for designing more efficient and safer structural components in demanding applications such as the automotive and aerospace industries.