Relating glass formation to eutectic composition in Cu100-xZrx alloy by molecular dynamics simulation

The relationship between eutectic compositions and glass-forming ability (GFA) in Cu_100-xZr_x (x = 8–83) system is studied by molecular dynamic (MD) simulation based on the embedded atom method (EAM). Local maxima of GFA occur in Cu₅₆Zr₄₄, Cu₄₇Zr₅₃ and Cu₃₁Zr₆₉ alloys, close to eutectic points in Cu-Zr binary phase diagram. The structural parameters indicate that the heterogeneous Cu-Zr pairs exhibit stronger and more stable interaction than that of homogeneous pairs. The small peak with a negative amplitude ahead of the main peak in S_CuZr(Q) also implies the preference of Cu-Zr pairs. The avoidance of Cu-Cu neighbours and Zr-Zr neighbours, which correspond to the prepeak prior to the main peak of S_CuCu(Q) and S_ZrZr(Q), leads to structural order on intermediate length scales. Perfect and defect icosahedra constitute medium range order (MRO) clusters by sharing atoms, which promotes the glass formation.