Studies on low-temperature stability of decagonal Al–Co–Ni

Abstract

The stability of decagonal Al–Co–Ni (d-phase) has been investigated by in situ single-crystal X-ray diffraction, at temperatures between room (RT) and 20 K, as well as at 90 and 473 K, under a pressure of 2.8 GPa. Samples of the Ni-rich basic d-phase, as well as superstructure type I, have been studied. Besides a slight variation in reflection intensities, no phase transition could be observed under the given conditions. This is no proof, however, for the low-temperature (LT) stability of the d-phase, since high-energy ball-milling experiments at RT lead to a transition of the d-phase to the β-phase, i.e. the disordered B2-type.

Acknowledgement

Financial support under grant SNF 200020-105158 is gratefully acknowledged.