Effect of alloying elements on the crystallization kinetics of Mg–Cu–(Y, Gd) bulk amorphous alloys

In the present study, the effect of alloying elements on the crystallization kinetics of the Mg–Cu–(Y, Gd) bulk amorphous alloys has been investigated using thermal analysis (DTA) and EXAFS. The calculated CCT diagrams show that Mg65Cu25Gd10 alloy has a much lower critical cooling rate (i.e., higher glass forming ability) than Mg65Cu25Y10 alloy. Isothermal annealing studies of the alloys also show that Mg65Cu25Gd10 alloy has a higher resistance to crystallization during annealing than Mg65Cu25Y10 alloy. Difference in the glass forming abilities between Mg65Cu25Gd10 and Mg65Cu25Y10 alloys has been explained by the differences in the effective atomic sizes in amorphous state. It has also been shown that there are different local atomic configuration changes during annealing between Mg65Cu25Gd10 and Mg65Cu25Y10 alloys, which are related to the glass stability of these alloys.