Mechanical Properties and Microstructure of Magnesium Alloy with In Situ Formed Al2RE Phases

Abstract

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 57.6GPa 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.