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

In present work, we researched the relationships between ΔHm and critical cooling rate Rc 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 Zmax up to Ø7.5 mm are also developed by us in the light of the optimum ΔHm of Zr–Al–Ni–Cu alloy system. The results show that the relationships between ΔHm and Rc are all concave upward parabolas, and the optimum ΔHms 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’ Rcs 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 ΔHm can be used for quickly predicting the alloy's GFA and helpful for the development of new BMGs.