A transmission electron microscopic study of icosahedral twins—I. Rapidly solidified Al-Mn-Fe alloys
1995; Elsevier BV; Volume: 43; Issue: 9 Linguagem: Inglês
10.1016/0956-7151(95)00024-p
ISSN1873-2879
Autores Tópico(s)Mineralogy and Gemology Studies
ResumoDendrites of the icosahedral quasicrystalline phase in an aluminium matrix were formed on rapid solidification of an Al90Mn5Fe5 alloy. A large number of these particles was found to be twinned with one of the five-fold symmetry axes as the twin axis, as established by careful tilting experiments in the transmission electron microscope. The twin relationship can be expressed in 60 different ways by a rotation around seven different axes of the icosahedron and utilising 12 different angles. In the alloys of composition Al86Mn7Fe7 and Al80Mn10Fe10 an icosahedral phase, Al3Fe and α-Al formed at wheel surface velocities above 23.5 m/s. The icosahedral phase in these alloys is not twinned. At 12 m/s wheel velocity only Al3Fe and α-Al formed. The relationship of the icosahedral twin to the decagonal phase has been brought out.
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