Natural quasicrystal with decagonal symmetry

Abstract

We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrystal, with composition Al71Ni24Fe5, was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite. Icosahedrite, Al63Cu24Fe13, the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al38Ni32Fe30), Fe-poor steinhardtite (Al50Ni40Fe10), Al-bearing trevorite (NiFe2O4) and Al-bearing taenite (FeNi). Laboratory studies of decagonal Al71Ni24Fe5 have shown that it is stable over a narrow range of temperatures, 1120 K to 1200 K at standard pressure, providing support for our earlier conclusion that the Khatyrka meteorite reached heterogeneous high temperatures [1100 < T(K) ≤ 1500] and then rapidly cooled after being heated during an impact-induced shock that occurred in outer space 4.5 Gya. The occurrences of metallic Al alloyed with Cu, Ni, and Fe raises new questions regarding conditions that can be achieved in the early solar nebula.

Shock synthesis of quasicrystals with implications for their origin in asteroid collisions

“…Quasicrystals can be synthesized in the laboratory by mixing precise ratios of selected elemental components in the liquid and quenching under strictly controlled conditions ranging from rapid to moderately slow (3,4). Nonetheless, the finding of two natural quasicrystals (5)(6)(7)(8) in the Khatyrka meteorite (9), which displays clear evidence of a shock generated by a high-velocity impact event (10), introduced a dramatic new possible mechanism of quasicrystal formation. Here, we report the results of a shock recovery experiment designed to reproduce some aspects of a collision that may have occurred between extraterrestrial bodies.…”

Al10Ni3Fe0.83, an Fe-depleted phase in the Al–Ni–Fe system

“…The second natural quasicrystal named decagonite has the composition Al 70.2 Ni 24.5 Fe 5.3 (Bindi et al, 2015), which is very similar to the synthetic phase Al 71 Ni 24 Fe 5 (Lemmerz et al, 1994). While simulating the growth mechanism of decagonite under high-pressure and high-temperature conditions (HPHT) by the high-pressure sintering (HPS) process, we obtained another phase in the ternary system Al-Ni-Fe (Raghavan, 2010) with composition Al 10 Ni 3 Fe 0.83 .…”

Dynamic stabilities of icosahedral-like clusters and their ability to form quasicrystals

“…1 and 2). The temperature is controlled by the Berendsen thermostat 37 and the Newtonian equation is integrated with a time step of 1 fs by applying the velocity Verlet algorithm; 1×10 6 MD steps are propagated ateach temperature point. The temperature is controlled from 100 K to a temperature higher than the bulk melting temperature of each metalcluster, and the temperature 065017-4 Liang, Hamid, and Duan AIP Advances 6, 065017 (2016) interval (∆T) is chosen as 20K.…”

“…2 Quasicrystals have already been shown to be important in hydrogen storage and as an aeronautical alloy. 3,4 The quasicrystal formed in nature is mainly composed of Al-Cu-Fe 5 (although the Al-Ni-Fe quasicrystal has also recently beendiscovered 6 ), and other quasicrystals have been synthesized. 2 Basically, the Al-based, 1,2,5-10 Zr-based, [11][12][13][14][15] and Ti-based [16][17][18] quasicrystals are of fundamental concern, although the reason why these are indispensable components in such quasicrystals still remains unclear.…”