Mechanical properties and microstructure of magnesium alloy with in situ formed Al₂RE phases

The advancement of magnesium alloys has historically faced challenges due to their inherently low modulus and the inverse relationship between modulus and ductility. In this study, an Mg-15Gd-⁸Y–¹¹Al-0.3Mn alloy containing Al₂RE phases was developed through an in-situ synthesis process, exhibiting exceptional mechanical properties, including a high elastic modulus of 57.6 GPa coupled with a satisfactory elongation of 7.3 %. The findings indicate the presence of polygonal Al₂RE phases of varying sizes within the alloy, with α-Mg observed in some Al₂RE phases, forming a coherent interface. The grain size of the alloy was refined, and the dimensions of the Al₂RE particles were reduced through the extrusion process. The effective strain transfer between α-Mg and Al₂RE, facilitated by the coherent interface, endowed the alloy with commendable ductility, even at a substantial Al₂RE volume fraction of 23 %. Furthermore, the formation of the Al₂RE phase was identified as the key contributor to the alloy's enhanced modulus. This study provides novel insights for the engineering of high-modulus magnesium alloys, thereby paving the way into their broader industrial application.