Influence of Yttrium Addition on the Mechanical Characteristics of Metallic Glass across Wide Strain Rates

Abstract

The stress-strain curves, glass-forming ability, and fracture properties of bulk metallic glasses with the composition Cu_47.5Zr_(45.5−x)Al₇Y_x, where yttrium content (x) is 1, 3, and 5 atomic percent (at%) are examined subjected to compressive strain rates between 10⁻³ and 4×10³ s⁻¹. The findings indicate that adding yttrium increases the reduced glass transition temperature T_rg. Moreover, the γ parameter, which indicates the ability to form glass, rises as the yttrium concentration goes from 0 to 3 at%, but experiences a slight decrease when the yttrium content is increased to 5 at%. In all the alloys that were tested, the fracture stress rises with increasing strain rates, whereas the fracture strain diminishes. The addition of 3 at% yttrium results in the highest fracture strain under tested conditions. The fracture surface observations reveal molten droplet structures, vein patterns, and dimples. The results demonstrate that strain rate and yttrium content are the primary factors influencing the fracture behavior of Cu_47.5Zr_(45.5-x)Al₇Y_x bulk metallic glasses.