Atomic Structure of Ca40+xMg25Cu35-x Metallic Glasses (Preprint)
Abstract
The atomic structures of four Ca40+XMg25Cu35-X (X = 0, 5, 10, and 20 at.%) ternary metallic glasses have been determined using a synergistic combination of neutron diffraction, quantum molecular dynamic (QMD) simulation and constrained reverse Monte Carlo modeling. The amorphous structure of these alloys can be described as close-packing of efficiently packed Cu-centered clusters that have Ca, Mg and Cu atoms in the first coordination shells. Experimental evidence is given for the presence of Cu atoms in inter-cluster sites for the two most Cu-rich glasses. The close-packed arrangement of clusters is present only within length scale a length scale of approximately 10 A providing a characteristic medium range order prepeak at Q approximately 1.2 A in the total scattering structure factors of these alloys. An average coordination number of 10 (with about 5-7 Ca, 2-3 Mg and 1-2 Cu atoms) is most common for the Cu-centered clusters. The average coordination numbers around Mg and Ca are 12-13 (approximately 6-8 Ca, 3 Mg and 1-4 Cu) and 13-15 (7-9 Ca, 3-4 Mg, and 2-5 Cu), respectively, and they are composition dependent.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2011
- Accession Number
- ADA554178
Entities
People
- C. F. Woodward
- Daniel Miracle
- E. R. Barney
- Oleg N. Senkov
- Y. Q. Cheng
Organizations
- Air Force Research Laboratory