scholarly journals Achieving strong and stable nanocrystalline Al alloys through compositional design

2021 ◽  
Author(s):  
Qiang Li ◽  
Jian Wang ◽  
Haiyan Wang ◽  
Xinghang Zhang
Keyword(s):  
Thermal Stability ◽  
Grain Refinement ◽  
Room Temperature ◽  
Supersaturated Solid Solution ◽  
High Strength ◽  
Al Alloys ◽  
Mechanical Anisotropy ◽  
Transition Metal Alloys ◽  
Mechanical Strengths ◽  
Tension Compression Asymmetry

Abstract Al alloys often suffer from low mechanical strength and lack high-temperature microstructural and mechanical robustness. A series of binary and ternary nanocrystalline (NC) Al transition metal alloys with supersaturated solid solution and columnar nanograins have been recently developed by using magnetron sputtering, manifesting a new realm of mechanical properties and thermal stability. Distinct solutes cause evident differences in the phase transformations and efficiencies for grain refinement and crystalline-to-amorphous transition. Certain sputtered Al-TM alloys have shown room-temperature mechanical strengths greater than 2 GPa and outstanding thermal stability up to 400 °C. In addition, the NC Al alloys show mechanical anisotropy and tension–compression asymmetry, revealed by micromechanical tests. Through the process encapsulating various compositionally distinct systems, we attempt to illuminate the solute effects on grain refinement and properties and more importantly, tentatively unravel the design criteria for high-strength and yet thermally stable NC Al alloys. Graphic Abstract

scholarly journals Achieving room-temperature brittle-to-ductile transition in ultrafine layered Fe-Al alloys

2020 ◽  
Vol 6 (39) ◽  
pp. eabb6658
Author(s):  
Lu-Lu Li ◽  
Yanqing Su ◽  
Irene J. Beyerlein ◽  
Wei-Zhong Han
Keyword(s):  
Room Temperature ◽  
Extreme Environments ◽  
High Strength ◽  
Layered Composite ◽  
Al Alloys ◽  
Brittle To Ductile Transition ◽  
Transmission Electron ◽  
Structural Applications ◽  
Wear And Corrosion Resistance ◽  
New Applications

Fe-Al compounds are of interest due to their combination of light weight, high strength, and wear and corrosion resistance, but new forms that are also ductile are needed for their widespread use. The challenge in developing Fe-Al compositions that are both lightweight and ductile lies in the intrinsic tradeoff between Al concentration and brittle-to-ductile transition temperature. Here, we show that a room-temperature, ductile-like response can be attained in a FeAl/FeAl2 layered composite. Transmission electron microscopy, nanomechanical testing, and ab initio calculations find a critical layer thickness on the order of 1 μm, below which the FeAl2 layer homogeneously codeforms with the FeAl layer. The FeAl2 layer undergoes a fundamental change from multimodal, contained slip to unimodal slip that is aligned and fully transmitting across the FeAl/FeAl2 interface. Lightweight Fe-Al alloys with room-temperature, ductile-like responses can inspire new applications in reactor systems and other structural applications for extreme environments.

Severe Plastic Deformation under High Pressure for Production of Superplastic Materials

2016 ◽  
Vol 838-839 ◽  
pp. 287-293 ◽  
Author(s):  
Zenji Horita
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
High Pressure Torsion ◽  
High Strength ◽  
Al Alloys ◽  
Strain Rates ◽  
Ti Alloys

Grain refinement is an important prerequisite for advent of superplasticity. In particular, as the grain size is smaller, the superplasticity appears at higher strain rates and lower temperatures. Severe plastic deformation (SPD) is a useful process for achieving significant grain refinement. This presentation shows that applicability of the SPD process is enhanced when it is operated under high pressure through high-pressure torsion (HPT) and high-pressure sliding (HPS). It is demonstrated that commercially available conventional alloys but less ductile alloys such as Mg alloys, age-hardenable high-strength Al alloys (A2024, A7075) and Ti alloys become superplastic after processing by HPT or HPS.

scholarly journals Thermal stability of Al2MgC2 and thermodynamic modeling of the Al–C–Mg system - Application to grain refinement of Mg–Al alloys

Calphad ◽  
2019 ◽  
Vol 67 ◽  
pp. 101678 ◽  
Author(s):  
G. Deffrennes ◽  
B. Gardiola ◽  
M. Lomello-Tafin ◽  
A. Pasturel ◽  
A. Pisch ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Refinement ◽  
Thermodynamic Modeling ◽  
System Application ◽  
Al Alloys ◽  
Thermal Stability Of

scholarly journals The Thermal Properties of L12 Phases in Aluminum Enhanced by Alloying Elements

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1420
Author(s):  
Jihang Lan ◽  
Zhaoqun Chen ◽  
Linghong Liu ◽  
Qingzhou Zhang ◽  
Mengdong He ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Density Functional ◽  
High Strength ◽  
Careful Analysis ◽  
Al Alloys ◽  
Functional Theory ◽  
Covalently Bonded ◽  
The Density Functional Theory ◽  
Firm Basis ◽  
Thermal Stability Of

The L12 type trialuminide compounds Al3M possess outstanding mechanical properties, which enable them to be ideal for dispersed strengthening phases for the high-strength thermally stable Al based alloys. Ab-initio calculations based on the density functional theory (DFT) were performed to study the structural, electronic, thermal, and thermodynamic properties of L12-Al3M (M = Er, Hf, Lu, Sc, Ti, Tm, Yb, Li, Mg, Zr) structures in Al alloys. The total energy calculations showed that the L12 structures are quite stable. On the basis of the thermodynamic calculation, we found that the Yb, Lu, Er, and Tm atoms with a larger atomic radii than Al promoted the thermal stability of the Al alloys, and the thermal stability rank has been constructed as: Al3Yb > Al3Lu > Al3Er > Al3Tm > Al, which shows an apparent positive correlation between the atomic size and thermal stability. The chemical bond offers a firm basis upon which to forge links not only within chemistry but also with the macroscopic properties of materials. A careful analysis of the charge density indicated that Yb, Lu, Er, and Tm atoms covalently bonded to Al, providing a strong intrinsic basis for the thermal stability of the respective structures, suggesting that the addition of big atoms (Yb, Lu, Er, and Tm) are beneficial for the thermal stability of Al alloys.

Grain Growth and Phase Formation in Ion Irradiated/Annealed Thin Ni-Al Alloys Films

1989 ◽  
Vol 157 ◽  
Author(s):  
Dale E. Alexander ◽  
Gary S. Was ◽  
Lynn E. Rehn
Keyword(s):  
Solid Solution ◽  
Grain Growth ◽  
Room Temperature ◽  
Supersaturated Solid Solution ◽  
Ion Irradiation ◽  
Al Alloys ◽  
Heat Of Mixing ◽  
Mixing Effect ◽  
Temperature Irradiation ◽  
Support Grid

ABSTRACTIon irradiation and annealing studies were performed on Ni, Ni-20 at.%Al multilayers and Ni-20 at.%Al co-evaporated thin films. Xe+ ions were used to irradiate the films and homogenize the multilayers at room temperature. Irradiation of alloy films formed a metastable, supersaturated solid solution of γ phase and an HCP phase. Ion induced grain growth occurred in all films. A factor of 2 greater growth was observed in Ni-Al multilayers compared with coevaporated films irradiated to the same dose. The enhancement is attributed to a heat of mixing effect. Post irradiation annealing of the mixed multilayers formed γ*, the morphology of which was dependent upon the presence of Cu in the films due to substrate mixing from the support grid.

SPD-Induced Grain Boundary Segregations and Superior Strength in UFG Al Alloys

2010 ◽  
Vol 667-669 ◽  
pp. 665-669
Author(s):  
Nariman A. Enikeev ◽  
Maxim Yu. Murashkin ◽  
Xavier Sauvage ◽  
Vil U. Kazykhanov ◽  
Ruslan Valiev
Keyword(s):  
Grain Size ◽  
Atom Probe Tomography ◽  
Room Temperature ◽  
High Strength ◽  
Atom Probe ◽  
Mean Value ◽  
Al Alloys ◽  
Ultrafine Grain ◽  
Ultrafine Grain Size ◽  
Grain Boundary Segregations

Two Al alloys (AA1570 and AA6061) in the solutionized state have been processed by HPT at room temperature to achieve a homogeneous UFG structure. After HPT, the grain size was found to have a mean value about 100 nm for both alloys. Measured yield stress values of HPT-produced UFG alloys being plotted in terms of the Hall-Petch relationship were found to exceed the plot predictions for the range of ultrafine grain size. For both alloys, Atom Probe Tomography measurements allowed to reveal segregation of solute elements along grain boundaries. The origin of the extremely high strength of the alloys nanostructured by HPT is discussed with a special attention to the influence of such segregations on the emission and the mobility of dislocations.

Microstructure of an extruded rapidly solidified Al-8Fe-2Mo alloy

1986 ◽  
Vol 44 ◽  
pp. 548-549
Author(s):  
W. T. Donlon ◽  
J. E. Allison ◽  
S. Shinozaki
Keyword(s):  
Electron Microscopy ◽  
Automotive Industry ◽  
Fuel Economy ◽  
High Strength ◽  
Al Alloys ◽  
Light Weight ◽  
Thin Sections ◽  
Strength And Durability ◽  
Rapidly Solidified ◽  
Whitney Aircraft

Light weight materials which possess high strength and durability are being utilized by the automotive industry to increase fuel economy. Rapidly solidified (RS) Al alloys are currently being extensively studied for this purpose. In this investigation the microstructure of an extruded Al-8Fe-2Mo alloy, produced by Pratt & Whitney Aircraft, Goverment Products Div. was examined in a JE0L 2000FX AEM. Both electropolished thin sections, and extraction replicas were examined to characterize this material. The consolidation procedure for producing this material included a 9:1 extrusion at 340°C followed by a 16:1 extrusion at 400°C, utilizing RS powders which have also been characterized utilizing electron microscopy.

ALUMINUM 713.0

Alloy Digest ◽  
1985 ◽  
Vol 34 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Room Temperature ◽  
High Strength ◽  
Heat Treating ◽  
Good Combination ◽  
Casting Alloy ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Permanent Mold Castings ◽  
Aluminum Base

Abstract ALUMINUM 713.0 is an aluminum-base casting alloy that ages at room temperature to provide high-strength sand and permanent-mold castings. It has a good combination of mechanical properties and its corrosion resistance is equivalent to that of the aluminum-silicon alloys. It is dimensionally stable. Among its many uses are housings, machinery parts, fittings, lever arms and brackets. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-263. Producer or source: Various aluminum companies.

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