Decagonal and related phases in Al-Mn alloys: electron diffraction and microstructure

Abstract

We present the first complete stereographic projection (Kikuchi band map) of the Al-Mn decagonal phase, determined from tilting experiments using selected-area diffraction (SAD) and convergent-beam diffraction (CBD). These new crystallographic data are indexed with existing schemes. A partial stereographic projection of a phase closely related to the decagonal phase, previously identified as orthorhombic Al₃Mn, is also determined with SAD and CBD. Good agreement between the stereographic projection and the SADs for Al₃Mn and those for the decagonal phase is demonstrated, indicating the degree to which the Al₃Mn phase is a decagonal approximate.