Al-Pd-Fe belongs to a group of alloy systems exhibiting formation of quasicrystals and allied periodic phases. According to the position of Fe in the periodic table this alloy system is related to the extensively studied Al-Pd-Mn ([1] and references therein) and Al-Pd-Co [2].
We report the investigation of the phase equilibria and phase transitions in Al-Pd-Fe in the compositional range of 50 to 100 at.% Al and temperature range of 750 to 1020 °C by scanning and transmission electron microscopy, energy-dispersive X-ray and differential thermal analyses, powder X-ray diffraction and inductively coupled plasma optical emission spectroscopy.
In the above mentioned temperature and concentration region ternary orthorhombic O-Al13(Fe,Pd)4 and N-phases and three ternary cubic phases designated C, C1 and C2 were revealed. The range of the Al-Pd orthorhombic e-phases extends up to ~10 at.% Fe. Apart from the four specific structural variants designated e6, e16, e22 and e28, irregular structures were observed in this continuous range. All above mentioned phases are closely structurally related to quasicrystals.
Formation of metastable decagonal phase was observed in at the cooling rates as low as 5 º/min. Depending on the composition the decagonal phase transforms either to multitwine e16 or the mixture of e16 and O-Al13(Fe,Pd)4.
The results partially are exposed in [3,4].
[1] B. Grushko, M. Yurechko, N. Tamura, J. Alloys Compd. 290 (1999) 164.
[2] M. Yurechko, B. Grushko, T. Velikanova, K. Urban, J. Alloys Compd. 337 (2002) 172.
[3] S. Balanetskyy, B. Grushko, E. Kowalska-Strzêciwilk, T.Ya. Velikanova, K. Urban, J. Alloys Compd. 364 (2004) 164.
[4] S. Balanetskyy, B. Grushko, T.Ya. Velikanova, K. Urban, J. Alloys Compd. In press