Electronegativity difference as a factor for evaluating the thermal stability of Al-rich metallic glasses

Abstract

This article proposes a factor, the critical electronegativity difference Δx _cri, to correlate alloy composition with thermal stability and glass-forming ability of Al–Ni–RE (RE: Rare Earth element) ternary metallic glasses. The Al-rich metallic glasses with Δx > Δx _cri exhibit glassy behavior, whereas alloys with Δx < Δx _cri are nanocrystalline. Nanoglassy alloys occur when Δx ≈ Δx _cri. The best glass formers are located near Δx _cri. Furthermore, an equation has been deduced to calculate Δx _cri with varying RE covalent atomic radius.

Keywords:

• electronegativity
• crystallization
• metallic glasses

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant Nos. 50471076) and the National Key Basic Research Program of China (No. 2007CB613906). Thanks are due to H. Yang for helpful discussions.