Quasicrystalline phases and their approximants in Al-Mn-Zn alloys
- Indian Inst. of Science, Bangalore (India)
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
Two Al-Mn-Zn alloys in melt-spun condition have been studied by transmission electron microscopy. The Al{sub 24}Mn{sub 5}Zn alloy was found to be fully icosahedral, while the Al{sub 12}Mn{sub 2.9}Zn alloy gave rise to decagonal quasicrystal. The decagonal phase grew in clusters with an orientation relationship between the grains suggesting nucleation on an icosahedral seed. On annealing at 500--600 C, the quasicrystalline phases transformed to a body centered orthorhombic phase L (a = 1.24, b = 1.26 and c = 3.05 nm) with a high density of planar defects. This phase transforms to an ordered and defect free monoclinic phase M, a superlattice structure of L (a = c = 1.77, b = 3.05 nm and {beta} = 89.1{degree}). The L phase is shown to be a rational approximant of the icosahedral phase. The interrelationship among quasicrystalline phases and their rational approximants in Al-Mn-Zn system are highlighted.
- Sponsoring Organization:
- Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 599739
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 12 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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