High-resolution electron microscopy of Al–Ni–Fe decagonal quasicrystal

Abstract

The structure of a stable decagonal quasicrystal with 0.4 nm periodicity, formed in a conventionally solidified alloy with composition Al 71.6 Ni 23.7 Fe 4.7 , was investigated by high-resolution electron microscopy. It was found that this decagonal phase is one of the best-ordered quasicrystals, without any detectable linear phason strain and with only weak random phason strain. The structure is interpreted as an aperiodic tiling of decagonal atom columns with a diameter of about 1.2 nm. The atomic arrangements in special local regions are discussed on the basis of computer simulations.

Twenty years of structure research on quasicrystals. Part I. Pentagonal, octagonal, decagonal and dodecagonal quasicrystals

“…A first structure model, AlFeNi-HYP-96, based on HRTEM investigations on d-Al 71.6 Fe 4.7 Ni 23.7 and in analogy to the model AlCoNi-HLS-91 was proposed by Hiraga, Yubuta, Park (1996). The fundamental structural unit was found to be a columnar cluster with % 12 A diameter (by a factor 1/t smaller than the cluster in d-Al--Co--Ni).…”

Metastable transformation states of decagonal Al-Co-Ni due to inhibited decomposition

“…This might be based on the finding that the quasicrystal at this composition does not show stable or metastable low-temperature quasicrystals or related structures without previous decomposition. 38,39 We have a similar situation in the Al-Ni-Fe system 40,41 at similar Al and Ni contents.…”

Phase composition and transformation behavior of readily solidified Al–Ni–Fe alloys in α-Al–decagonal phase region

“…A thermodynamically stable decagonal quasicrystalline phase in Al-Ni-Fe alloys is found in a narrow compositional range of Al 71.1-71.7 Ni 24.6-23.0 Fe 4.3-5.3 [9]. Within this range, a decagonal phase composition of Al 71.6 Ni 23.7 Fe 4.7 , with a periodicity of 0.4 nm along the decagonal axis, has been reported as one of the best-ordered quasicrystals [10,11]. The present work deals with this composition in order to investigate the possibility of precipitating the decagonal phase in an aluminum matrix to obtain a material with good mechanical properties.…”

“…The present work deals with this composition in order to investigate the possibility of precipitating the decagonal phase in an aluminum matrix to obtain a material with good mechanical properties. In addition, a decagonal phase composition of Al 75 Ni 10 in Al-Ni-Fe system [12], is also included in this study to extend the observations. This second decagonal phase composition is enriched in Fe and has a periodicity of 1.6 nm along the decagonal axis.…”