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Results for “Al-Cu-Fe”

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12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Thermal spray coating of Al-Cu-Fe quasicrystals: Dynamic observations and surface properties

In this study, we prepared Al-Cu-Fe quasicrystals (QCs) via thermal spray coating after optimizing the process parameters. Both in-situ XRD and in-situ TEM were used to investigate the thermal stability of QC phase. These dynamic techniques uniquely allow for a direct observation of QC growth upon heating and cooling. We show that the cubic β-Al-Cu-Fe is the dominant phase at room temperature (initial stage), but with an increase in temperature, the QC takes over at 650 °C, consistent with thermodynamic calculations. Further increasing the temperature to 800 °C, the QC phase transforms into cubic β-Al-Cu-Fe such that the β-Al-Cu-Fe phase is the only phase in existence at 870 °C. Based on this result, we annealed the sample after thermal spray deposition for one hour at 650 °C, which yielded an almost pure QC coating. The contact angle (against water) before annealing was 50°±4° but improved dramatically to 130°±5° after annealing at 650 °C for 1 h. Here, this study provides a better understanding of QC formation during heat treatment as well as that of other secondary phases. Furthermore, these results can be used to manufacture QC coatings with enhanced interfacial properties that are central to technological applications.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

A study on spherical particles in Al65Cu20Fe15 alloy prepared by arc melting

Highlights: • Spherical particles and facets were found. • Spherical particles consist of quasicrystalline grains embedded in single crystal matrix. • Facets were found on the surface of spherical particles, which can be classified to three types. • A model for the formation of spherical particles is suggested. • Reasons for the formation of facets are discussed. - Abstract: Al-Cu-Fe alloys are important due to reports that stable icosahedral quasicrystalline phase with composition in the vicinity of Al{sub 65}Cu{sub 20}Fe{sub 15} can be prepared. However, it has been widely reported that the as-prepared alloy, very often by arc-melting, is porous, consisting of particles with different morphologies. Among these, one type of particles of a spherical shape is considered as pure cubic β phase in previous reports. In this research, this spherical particle was studied using a Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy, Transmission Electron Microscope, and Electron Diffraction. It was found that the particles are not single phase, consisting of icosahedral quasicrystalline grains embedded inside single crystal matrix of τ phase. Additionally, there are places where the τ phase appears to have out-most layer enriched in Cu. The surface of the particles is faceted and the facets can be classified to three types according to their detailed structures. A close examination and analysis led to the conclusion that these three types are parallel to the atomic planes of {1 1 0}, {1 1 1}, and {1 0 0}, respectively. A model for the spherical particle formation is suggested and the reasons for the formation of facets are discussed. This report is valuable in clarifying some discrepancies in previous reports, and in understanding the phase development in an Al-Cu-Fe alloy system.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Microstructure and mechanical properties of aluminium matrix composites reinforced by Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} melt spun ribbon

Aluminium matrix composites containing 15, 30 and 50 vol.% of pulverized Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} (in at.%) melt spun ribbons have been prepared by a vacuum hot pressing (T = 673 K, P = 600 MPa). The microstructure of the initial ribbon and the composites was investigated using X-ray, scanning and transmission electron microscopy. In the as-spun ribbon the quasicrystalline icosahedral phase (i-phase) coexisted with the cubic copper rich β-Al(Cu, Fe) intermetallic compound. The phase composition of Al-Cu-Fe particles changed after consolidation process and the i-phase transformed partially to the ω-Al{sub 70}Cu{sub 20}Fe{sub 10} phase. Additionally, the Θ-Al{sub 2}Cu phase formed at the α(Al)/Al-Cu-Fe particle interfaces. With an increase in volume fraction of the reinforcement the hardness of the composites increased up to HV = 180 for the highest amount of added particles. The ultimate compression strength of the same sample reached the value of 545 MPa. - Highlights: • Al and 15, 30, 50% of pulverized Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} melt spun ribbon were consolidated. • The initial ribbon consisted of the icosahedral i-phase and copper rich β-Al(Cu, Fe). • The i-phase partially transforms to ω-Al{sub 7}Cu{sub 2}Fe phase in all composites. • Increase of microhardness and compressive strength with content of reinforcement • Ultimate compression strength 545 MPa for 50% of added particles.

36 MATERIALS SCIENCE↗
DOE OSTI2016

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

Here, we designed a plate impact shock recovery experiment to simulate the starting materials and shock conditions associated with the only known natural quasicrystals, in the Khatyrka meteorite. At the boundaries among CuAl5, (Mg 0.75 Fe 0.25 2+ ) 2 SiO 4 olivine, and the stainless steel chamber walls, the recovered specimen contains numerous micron-scale grains of a quasicrystalline phase displaying face-centered icosahedral symmetry and low phason strain. The compositional range of the icosahedral phase is Al 68-73 Fe 11-16 Cu 10-12 Cr 1-4 Ni 1-2 and extends toward higher Al/(Cu+Fe) and Fe/Cu ratios than those reported for natural icosahedrite or for any previously known synthetic quasicrystal in the Al-Cu-Fe system. The shock-induced synthesis demonstrated in this experiment reinforces the evidence that natural quasicrystals formed during a shock event but leaves open the question of whether this synthesis pathway is attributable to the expanded thermodynamic stability range of the quasicrystalline phase at high pressure, to a favorable kinetic pathway that exists under shock conditions, or to both thermodynamic and kinetic factors.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2019

Materials Data on Al39Fe7Cu24 by Materials Project

Fe7Cu24Al39 crystallizes in the cubic Pm-3 space group. The structure is three-dimensional. there are three inequivalent Fe sites. In the first Fe site, Fe is bonded to twelve equivalent Fe atoms to form face-sharing FeFe12 cuboctahedra. All Fe–Fe bond lengths are 2.46 Å. In the second Fe site, Fe is bonded to six Fe, three Cu, and three equivalent Al atoms to form distorted FeAl3Fe6Cu3 cuboctahedra that share a cornercorner with one FeAl3Fe6Cu3 cuboctahedra and faces with eleven FeFe12 cuboctahedra. There are one shorter (2.27 Å) and four longer (2.67 Å) Fe–Fe bond lengths. There are two shorter (2.60 Å) and one longer (2.93 Å) Fe–Cu bond lengths. There are one shorter (2.50 Å) and two longer (2.81 Å) Fe–Al bond lengths. In the third Fe site, Fe is bonded in a cuboctahedral geometry to twelve equivalent Al atoms. All Fe–Al bond lengths are 2.60 Å. There are four inequivalent Cu sites. In the first Cu site, Cu is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Cu–Al bond distances ranging from 2.55–2.80 Å. In the second Cu site, Cu is bonded in a 6-coordinate geometry to two equivalent Fe and six Al atoms. There are two shorter (2.46 Å) and four longer (2.55 Å) Cu–Al bond lengths. In the third Cu site, Cu is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Cu–Al bond distances ranging from 2.58–2.70 Å. In the fourth Cu site, Cu is bonded in a 7-coordinate geometry to one Fe and six Al atoms. There are a spread of Cu–Al bond distances ranging from 2.50–2.68 Å. There are six inequivalent Al sites. In the first Al site, Al is bonded in a 6-coordinate geometry to three equivalent Fe and five Cu atoms. In the second Al site, Al is bonded in a 6-coordinate geometry to six Cu atoms. In the third Al site, Al is bonded in a 2-coordinate geometry to one Fe and one Cu atom. In the fourth Al site, Al is bonded in a 4-coordinate geometry to four Cu atoms. In the fifth Al site, Al is bonded in a 11-coordinate geometry to five Cu atoms. In the sixth Al site, Al is bonded in a 5-coordinate geometry to five Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al7FeCu2 by Materials Project

Al7Cu2Fe crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. Fe is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Fe–Al bond distances ranging from 2.43–2.48 Å. Cu is bonded in a 10-coordinate geometry to two equivalent Cu and eight Al atoms. Both Cu–Cu bond lengths are 2.56 Å. There are a spread of Cu–Al bond distances ranging from 2.53–2.68 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 5-coordinate geometry to one Fe and four equivalent Cu atoms. In the second Al site, Al is bonded in a 4-coordinate geometry to one Fe and three equivalent Cu atoms. In the third Al site, Al is bonded in a distorted bent 150 degrees geometry to two equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al37(Fe6Cu)2 by Materials Project

Al37(Fe6Cu)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are ten inequivalent Fe sites. In the first Fe site, Fe is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Fe–Al bond distances ranging from 2.45–2.78 Å. In the second Fe site, Fe is bonded in a 10-coordinate geometry to one Cu and nine Al atoms. The Fe–Cu bond length is 2.60 Å. There are a spread of Fe–Al bond distances ranging from 2.41–2.76 Å. In the third Fe site, Fe is bonded in a 11-coordinate geometry to one Cu and ten Al atoms. The Fe–Cu bond length is 2.82 Å. There are a spread of Fe–Al bond distances ranging from 2.42–2.82 Å. In the fourth Fe site, Fe is bonded in a 11-coordinate geometry to eleven Al atoms. There are a spread of Fe–Al bond distances ranging from 2.45–2.88 Å. In the fifth Fe site, Fe is bonded in a 10-coordinate geometry to one Cu and nine Al atoms. The Fe–Cu bond length is 2.62 Å. There are a spread of Fe–Al bond distances ranging from 2.44–2.64 Å. In the sixth Fe site, Fe is bonded in a 10-coordinate geometry to one Cu and nine Al atoms. The Fe–Cu bond length is 2.65 Å. There are a spread of Fe–Al bond distances ranging from 2.44–2.61 Å. In the seventh Fe site, Fe is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Fe–Al bond distances ranging from 2.35–2.62 Å. In the eighth Fe site, Fe is bonded in a 9-coordinate geometry to one Cu and eight Al atoms. The Fe–Cu bond length is 2.59 Å. There are a spread of Fe–Al bond distances ranging from 2.33–2.63 Å. In the ninth Fe site, Fe is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Fe–Al bond distances ranging from 2.44–2.70 Å. In the tenth Fe site, Fe is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Fe–Al bond distances ranging from 2.45–2.72 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded in a 11-coordinate geometry to four Fe and seven Al atoms. There are a spread of Cu–Al bond distances ranging from 2.38–2.62 Å. In the second Cu site, Cu is bonded in a 10-coordinate geometry to two Fe and eight Al atoms. There are a spread of Cu–Al bond distances ranging from 2.56–2.74 Å. There are twenty-six inequivalent Al sites. In the first Al site, Al is bonded in a linear geometry to two equivalent Fe and two equivalent Al atoms. Both Al–Al bond lengths are 2.99 Å. In the second Al site, Al is bonded in a linear geometry to two equivalent Fe and four Al atoms. There are two shorter (2.96 Å) and two longer (2.97 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 3-coordinate geometry to three Fe and three Al atoms. There are a spread of Al–Al bond distances ranging from 2.67–2.88 Å. In the fourth Al site, Al is bonded in a 3-coordinate geometry to three Fe and two Al atoms. There are one shorter (2.67 Å) and one longer (2.85 Å) Al–Al bond lengths. In the fifth Al site, Al is bonded in a 4-coordinate geometry to three Fe, one Cu, and three Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.87 Å. In the sixth Al site, Al is bonded in a 5-coordinate geometry to three Fe, two Cu, and three Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.86 Å. In the seventh Al site, Al is bonded in a 2-coordinate geometry to two Fe and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.96 Å. In the eighth Al site, Al is bonded in a 8-coordinate geometry to two Fe, one Cu, and seven Al atoms. There are a spread of Al–Al bond distances ranging from 2.71–2.99 Å. In the ninth Al site, Al is bonded in a 2-coordinate geometry to three Fe and four Al atoms. There are a spread of Al–Al bond distances ranging from 2.65–2.85 Å. In the tenth Al site, Al is bonded in a 12-coordinate geometry to three Fe, one Cu, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–2.90 Å. In the eleventh Al site, Al is bonded in a 3-coordinate geometry to three Fe, one Cu, and one Al atom. The Al–Al bond length is 2.68 Å. In the twelfth Al site, Al is bonded in a 3-coordinate geometry to three Fe, one Cu, and one Al atom. The Al–Al bond length is 2.70 Å. In the thirteenth Al site, Al is bonded in a 2-coordinate geometry to three Fe and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.66–2.83 Å. In the fourteenth Al site, Al is bonded in a 2-coordinate geometry to three Fe and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.67–2.88 Å. In the fifteenth Al site, Al is bonded in a 4-coordinate geometry to four Fe and six Al atoms. There are a spread of Al–Al bond distances ranging from 2.83–2.89 Å. In the sixteenth Al site, Al is bonded in a 11-coordinate geometry to four Fe and seven Al atoms. There are one shorter (2.56 Å) and one longer (2.77 Å) Al–Al bond lengths. In the seventeenth Al site, Al is bonded in a 11-coordinate geometry to four Fe and seven Al atoms. There are one shorter (2.56 Å) and one longer (2.75 Å) Al–Al bond lengths. In the eighteenth Al site, Al is bonded in a distorted bent 150 degrees geometry to two Fe and two Al atoms. The Al–Al bond length is 2.71 Å. In the nineteenth Al site, Al is bonded in a distorted bent 150 degrees geometry to two Fe and two Al atoms. The Al–Al bond length is 2.70 Å. In the twentieth Al site, Al is bonded in a 10-coordinate geometry to three Fe and seven Al atoms. In the twenty-first Al site, Al is bonded in a 10-coordinate geometry to three Fe and seven Al atoms. In the twenty-second Al site, Al is bonded in a 1-coordinate geometry to three Fe, one Cu, and two equivalent Al atoms. In the twenty-third Al site, Al is bonded in a 10-coordinate geometry to three Fe and seven Al atoms. The Al–Al bond length is 2.51 Å. In the twenty-fourth Al site, Al is bonded in a 11-coordinate geometry to four Fe and seven Al atoms. There are one shorter (2.53 Å) and one longer (2.57 Å) Al–Al bond lengths. In the twenty-fifth Al site, Al is bonded in a 11-coordinate geometry to four Fe, one Cu, and six Al atoms. In the twenty-sixth Al site, Al is bonded in a 11-coordinate geometry to four Fe and seven Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al2FeCu by Materials Project

FeCuAl2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two FeCuAl2 ribbons oriented in the (1, 0, 0) direction. Fe is bonded in a linear geometry to two equivalent Al atoms. Both Fe–Al bond lengths are 2.51 Å. Cu is bonded in a linear geometry to two equivalent Al atoms. Both Cu–Al bond lengths are 2.51 Å. Al is bonded in a linear geometry to one Fe and one Cu atom.

36 MATERIALS SCIENCE↗