The present study reports the effect of the addition of Be in Cu-Zr bulk metallic glass (BMG) on glass-forming ability (GFA), plasticity and structural change. Although Be has a negative enthalpy of mixing with all the constituent elements of these glasses, Cu47.5Zr40Be12.5 alloy exhibits apparent double glass transitions (Tg) and enhanced plasticity as well as improved GFA. Intensive structural analysis using extended X-ray absorption fine structure suggests that a large difference in the enthalpy of mixing between atom pairs in multi-component BMGs can cause atomic scale structural inhomogeneity and/or locally favored structures in the amorphous matrix, resulting in enhanced compressive strains, although the enthalpies of mixing for atom pairs are all negative. This concept may shed light on the development of BMGs with large plasticity as well as high GFA.
Bibliographical noteFunding Information:
This work was supported by the Global Research Laboratory Program of the Korean Ministry of Science. One of the authors (E.S. Park) was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2006-214-D00066). The authors are grateful to Prof. K. Hono at NIMS, Japan, for the 3DAP-FIM experiment, and the authorities concerned with the Pohang Light Source (PLS) for XAS measurements. The author is indebted to Prof. Frans Spaepen, Harvard University, for thoughtful advice.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys