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Starting from the Zn17Sc3 cubic approximant, new quasicrystal alloys were searched by replacement of Zn with transition elements, T. In the cases of T=Mn, Fe, Co and Ni, new icosahedral quasicrystals are formed in as-cast alloys as major…

材料科学 · 物理学 2009-11-10 Ryo Maezawa , Shiro Kashimoto , Tsutomu Ishimasa

In a narrow composition range centered at Zn74.5Au10.5Yb15.0, Tsai-type icosahedral quasicrystal is formed in alloys quenched from 880 C. This quasicrystal belongs to the primitive type with the 6-dimensional lattice parameter a6D=7.378 A.…

材料科学 · 物理学 2020-01-08 Tsutomu Ishimasa

Structural studies on the icosahedral quasicrystals in Zn-Mg-Sc, Cu-Ga-Mg-Sc, and Zn-Mg-Ti alloys as well as their corresponding 1/1 cubic approximants, have revealed that these quasicrystals belong to a new structural group similar to…

材料科学 · 物理学 2009-11-10 Tsutomu Ishimasa , Yasushi Kaneko , Hiroshi Kaneko

A P-type icosahedral quasicrystal is formed in Au-Al-Yb alloy of which 6-dimensional lattice parameter a6D = 7.448 {\AA}. The composition of the quasicrystal was analyzed to be Au51Al34Yb15. This quasicrystal is formed in as-cast alloys,…

材料科学 · 物理学 2015-05-27 Tsutomu Ishimasa , Yukinori Tanaka , Shiro Kashimoto

Realization of an elemental solid-state quasicrystal has remained a distant dream so far in spite of extensive work in this direction for almost two decades. Here, we report the discovery of quasiperiodic ordering in a thick layer of…

In this work, we present the formation and characterization of a quaternary (pseudo ternary) icosahedral quasicrystal in Al65Ga5Pd17Mn13 alloy. The X ray diffraction and transmission electron microscopy confirmed the formation of…

材料科学 · 物理学 2009-11-13 T. P. Yadav , M. A. Shaz , R. S. Tiwari , O. N. Srivastava

Aluminium alloy AA7075 (Al-Zn-Mg-Cu) specimens were prepared using selective laser melting, also known as powder bed fusion additive manufacturing. In the as-manufactured state, which represents a locally rapidly solidified condition, the…

The discovery of quasicrystals 30 years ago challenged our understanding of order at the atomic scale. While quasicrystals possess long-range orientational order they lack translation periodicity. Structurally complex, yet crystalline…

材料科学 · 物理学 2014-10-14 Wolfgang Hornfeck , Raphael Kobold , Matthias Kolbe , Dieter Herlach

We have discovered a new compound of the composition ScPd2Al3 crystallizing in unknown structure type. Moreover, ScPd2Al3 reveals polymorphism. We have found an orthorhombic crystal structure at room temperature and a high temperature cubic…

Quasicrystals are fascinating structures, characterized by strong positional order but lacking the periodicity of a crystal. In colloidal systems, quasicrystals are typically predicted for particles with complex or highly specific…

软凝聚态物质 · 物理学 2022-02-28 Etienne Fayen , Marianne Impéror-Clerc , Laura Filion , Giuseppe Foffi , Frank Smallenburg

We report a novel kind of dodecagonal quasicrystal that has so far never been observed, nor theoretically predicted. It is composed of axially stacked hexagonal particle layers, with 12-fold rotational symmetry induced by 30 degrees…

软凝聚态物质 · 物理学 2015-04-16 Alfredo Metere , Peter Oleynikov , Mikhail Dzugutov , Sven Lidin

The dodecagonal quasicrystal classified into the five-dimensional space group P126/mmc, recently discovered in a Mn-Cr-Ni-Si alloy, has been analyzed using atomic-resolution spherical aberration-corrected electron microscopy, i.e.…

材料科学 · 物理学 2016-02-17 Tsutomu Ishimasa , Shuhei Iwami , Norihito Sakaguchi , Ryo Oota , Marek Mihalkovic

The first complete ab initio zero-temperature ternary phase diagram is constructed from the calculated energies of the elemental, binary and ternary Ti-Zr-Ni phases; for this, the icosahedral i-TiZrNi quasicrystal phase is approximated by…

材料科学 · 物理学 2007-05-23 R. G. Hennig , A. E. Carlsson , K. F. Kelton , C. L. Henley

"Seek and ye shall find, the unsought shall go undetected." This adage, attributed to Aristophanes' can be considered one of the defining mantras of new materials research; if you don't look, you certainly will not discover. As a result of…

Selective laser melting (SLM) is rapidly evolving to become a mainstream technology. However, the fundamental mechanisms of solidification and microstructure development inherent to the non-equilibrium conditions of this additive…

A dodecagonal quasicrystal showing 12-fold symmetry forms in Mn-rich quaternary alloys containing 5.5 or 7.5 at.% Cr, 5.0 at.% Ni and 17.5 at.% Si. After annealing at 700 C for 130 h, the quasicrystal precipitated in a matrix of \b{eta}-Mn…

材料科学 · 物理学 2016-02-17 Shuhei Iwami , Tsutomu Ishimasa

This work provides unambiguous evidence for the occurrence of icosahedral quasicrystal (iQC) enhanced nucleation during selective laser melting of gas atomized commercially-pure Ni powders. This solidification mechanism, which has only been…

材料科学 · 物理学 2022-01-17 C. Galera-Rueda , X. Jin , J. LLorca , M. T. Pérez-Prado

A structure model of atoms of two sizes, interacting with Lennard-Jones potentials and simulated by molecular dynamics, was observed to freeze into a decagonal quasicrystal dominated by Frank-Kasper coordination shells and closely related…

凝聚态物理 · 物理学 2009-10-28 Johannes Roth , Christopher L. Henley

Quasicrystals are frequently encountered in condensed matter. They are important candidates for equilibrium phases from the atomic scale to the nanoscale. Here, we investigate the computational self-assembly of four quasicrystals in a…

材料科学 · 物理学 2017-06-26 Pablo F. Damasceno , Sharon C. Glotzer , Michael Engel

Quasicrystals exhibit long-range order but lack translational symmetry. When grown as single crystals, they possess distinctive and unusual properties owing to the absence of grain boundaries. Unfortunately, conventional methods such as…

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