STUDY OF DECAGONAL QUASI-CRYSTALLINE PHASE-FORMATION IN THE AL-NI-FE ALLOY SYSTEM

Part of the Al-Ni-Fe alloy system, including the region of the decagon al phase, was studied by scanning electron microscopy, energy-dispersi ve X-ray analysis, X-ray diffractometry and transmission electron micr oscopy. The decagonal phase is thermodynamically stable in a narrow co mpositional range around Al71Ni24Fe5. At a temperature of about 940-de grees-C it transforms to Al13(Fe, Ni)4, Al3(Ni, Fe)2 and the liquid ph ase, and between 800 and 850-degrees-C to Al13(Fe, Ni)4, Al3(Ni, Fe) a nd Al3(Ni, Fe)2. The phase exhibits X-ray and electron diffraction pat terns similar to those of the Al-Cu-Co decagonal phase.