Thermodynamic and Kinetic Studies of Glass-Forming Compositions in Ca‒Mg‒Cu Ternary Metallic Glasses

Abstract

Herein, we systematically studied the thermodynamic and kinetic aspects of glass forming compositions in Ca–Mg–Cu alloy obtained by drawing the isocontour. Parameter \({{P}_{{{\text{HS}}}}}\) derived from the enthalpy of chemical mixing (ΔH_chem) and normalized mismatch entropy (\(\Delta {{S}_{\sigma }}/{{k}_{{\text{B}}}}\)) is used as a glass-forming ability (GFA) parameter. Variation of \({{P}_{{{\text{HS}}}}}\) with reported and calculated compositions is evaluated. Linear relation of Cu with \({{P}_{{{\text{HS}}}}}\) is observed, whereas inverse relation of Ca and Mg is obtained. The linear variation of \({{P}_{{{\text{HS}}}}}\) with a supercooled liquid region (SCLR) (\(\Delta {{T}_{{\text{x}}}}\)) is studied. Inverse correlation of critical cooling rate (\({{R}_{{\text{C}}}}\)) with \({{P}_{{{\text{HS}}}}}\) is obtained. \({{R}_{{\text{C}}}}\) for predicted compositions is found close to that of reported compositions. Therefore, Cu should be added carefully with other elements to improve the GFA and reduce the cooling rate of Ca‒Mg‒Cu glassy. In this paper, an empirical correlation of \(\Delta {{T}_{{\text{x}}}}\) with \({{P}_{{{\text{HS}}}}}\) is proposed, and the modeled values are found to agree with the experimental values.