Formation and stability of complex metallic phases including quasicrystals explored through combinatorial methods

Abstract

Aluminum-based quasicrystals typically form across narrow composition ranges within binary to quaternary alloys, which makes their fabrication and characterization challenging. Here, we use combinatorial approaches together with fast characterization techniques to study a wide compositional range including known quasicrystal forming compositions. Specifically, we use magnetron co-sputtering to fabricate libraries of ~140 Al-Cu-Fe and ~300 Al-Cu-Fe-Cr alloys. The alloys compositions are measured through automated energy dispersive X-ray spectroscopy. Phase formation and thermal stability are investigated for different thermal processing conditions (as-sputtered and annealed at 400 °C, 520 °C and 600 °C for Al-Cu-Fe libraries; annealed at 600 °C for Al-Cu-Fe-Cr libraries) using automated X-ray diffraction and transmission electron microscopy. In both systems the compositional regions across which the quasicrystalline phase forms are identified. In particular, we demonstrate that the quasicrystalline phase forms across an unusually broad composition range in the Al-Cu-Fe-Cr system. Additionally, some of the considered alloys vitrify during sputtering, which also allows us to study their nucleation behavior. We find that phases with polytetrahedral symmetry, such as the icosahedral quasicrystal and the λ-Al 13 Fe 4 phase, exhibit higher nucleation rates but lower growth rates, as compared to other phases with a lower degree of polytetrahedral order. Altogether, the here used combinatorial approach is powerful to identify compositional regions of quasicrystals.

Combinatorial measurement of critical cooling rates in aluminum-base metallic glass forming alloys

“…For cooling rates above ~ 10 16 K/s all alloys and even elemental metals form glasses 52 . When decreasing the cooling rate to ~ 10 9 K/s a large fraction, ~ 50% has been observed to form glasses 29 , 53 , 54 . For cooling rates around 10 3 K/s it had been estimated, based on extrapolations from experimental results that 10 6 alloys are potential bulk metallic glass formers 4 .…”

Review of the Design of Titanium Alloys with Low Elastic Modulus as Implant Materials

“…[ 143–145 ] Then the electron probe microanalysis (EPMA), X‐ray fluorescence, X‐ray diffraction, nanoindentation, and other techniques would be used to measure and obtain local compositions, crystal structures, and/or properties (e.g., hardness, elastic modulus, electrical conductivity, thermal expansion coefficients, and so on). This approach has been used in the design of many kinds of materials such as high‐entropy alloys, [ 146–149 ] bulk metallic glasses, [ 145,150–152 ] and Ti alloys [ 153–155 ] including those with a low elastic modulus. Teixeira et al [ 156 ] used a laser to deposit the pure Ti and pure Ta powders on a substrate to develop Ti–Ta alloys for biomedical applications.…”

“…electrical conductivity, thermal expansion coefficients, and so on). This approach has been used in the design of many kinds of materials such as high-entropy alloys, [146][147][148][149] bulk metallic glasses, [145,[150][151][152] and Ti alloys [153][154][155] including those with a low elastic modulus. Teixeira et al [156] used a laser to deposit the pure Ti and pure Ta powders on a substrate to develop Ti-Ta alloys for biomedical applications.…”

First synthesis of a unique icosahedral phase from the Khatyrka meteorite by shock-recovery experiment

“…5), which may be one of the reasons that its Al and Cu/Fe content are such a close match to natural i-phase II. Moreover, Wolf et al (2019) analyzed semiequilibrated Al-Cu-Fe-Cr samples made by co-sputtering followed by quick annealing and observed a high Cr i-phase with Al 63-65 Cu 12-22 Fe 5-11 Cr 6-15 composition. This suggests that metastable i-phases can incorporate significant Cr.…”