Relationship between melting enthalpy Δ Hm and critical cooling rate Rc for bulk metallic glasses

Abstract

In present work, we researched the relationships between Δ H m and critical cooling rate R c of five bulk metallic glass (BMG) systems, such as Mg–Ni–Nd, Pd–Cu–Si, La–Al–Ni–Cu, Zr–Al–Ni–Cu and Zr–Ti–Ni–Cu–Be, respectively, and five Zr–Al–Ni–Cu bulk metallic glasses with critical dimension Z max up to Ø7.5 mm are also developed by us in the light of the optimum Δ H m of Zr–Al–Ni–Cu alloy system. The results show that the relationships between Δ H m and R c are all concave upward parabolas, and the optimum Δ H ms for Mg–Ni–Nd, Pd–Cu–Si, Zr–Al–Ni–Cu, Zr–Ti–Ni–Cu–Be and La–Al–Ni–Cu are 10.3960, 21.2202, 19.7146, 18.1455 and 13.1558 KJ mol −1, respectively. Furthermore, other BMG’ R cs predicted by above-mentioned relationships satisfactorily agree with the tested results, which indicates that these relationships are reliable. However, the predicted results are reliable only if the main components are similar with the fitted BMG system or the additive is sparkle enough that the alloy's characteristic is not changed. On the whole, the Δ H m can be used for quickly predicting the alloy's GFA and helpful for the development of new BMGs.