Aluminum-Based Amorphous Alloys with Tensile Strength above 980 MPa (100 kg/mm<sup>2</sup>)

Inoue, Akihisa; Ohtera, Katsumasa; Tsai, A.‐P.; Masumoto, T.

doi:10.1143/jjap.27.l479

Cited by 379 publications

(142 citation statements)

References 14 publications

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“…Aluminum based metallic glasses (MG) exhibit good ductility combined with a higher strength compared to conventional aluminum based alloys [1]. At appropriate conditions, both thermal and mechanical treatment of Al based metallic glasses were shown to result in the formation of fcc-Al nanoprecipitates embedded in an Al-depleted amorphous matrix which results in improved mechanical properties compared to the single phase amorphous alloy prior to heat treatment [2].…”

Section: Introductionmentioning

confidence: 99%

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Dittrich

Schumacher

2014

Materials Science and Engineering: A

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Section: Introductionmentioning

confidence: 99%

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Dittrich

Schumacher

2014

Materials Science and Engineering: A

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“…The T x level is the highest for LTM = Fe and Co, followed by Ni and then Cu. Besides, we can recognize a linear relationship between E and T x , H v or σ f for Al-Y-Ni amorphous alloys 5 . The highest tensile strength of Al-Y-Ni amorphous alloys reaches 1140 MPa [5] .…”

Section: Al-based Amorphous Alloysmentioning

confidence: 99%

“…Besides, we can recognize a linear relationship between E and T x , H v or σ f for Al-Y-Ni amorphous alloys 5 . The highest tensile strength of Al-Y-Ni amorphous alloys reaches 1140 MPa [5] . Similar Al-based amorphous alloys with a good ductility were also found in Al-TM-RE (where TM = transition metals, RE = yttrium and rare earths) system by S. J. Poon et al [6][7][8] .…”

Section: Al-based Amorphous Alloysmentioning

confidence: 99%

Development and Applications of Highly Functional Al-based Materials by Use of Metastable Phases

et al. 2015

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In recent years, there has been a strong demand of developing advanced structural materials with functional properties such as high specific strength, high elevated temperature specific strength, high fatigue specific strength, low corrosion loss and low wear loss. This is because the practical uses of these functional structure materials are expected to cause the saving of material amount, reductions of material cost and energy during material production as well as the saving of consuming energy during practical uses. Besides, the light-weight materials with high corrosion resistance and high wear resistance are effective for the increase of endurance limit and the lightening of final products. Thus, the development of novel Al-based alloys having simultaneously the above-described functional properties is particularly important nowadays.As strengthening mechanisms for Al-based alloys, the following seven mechanisms are generally known 1 : solid solution, grain size refinement, work hardening, age hardening, precipitation, dispersion and defect-induced solute segregation. We have also noticed that the use of rapid quenching enables highly supercooled liquid solidification in conjunction with a high nucleation rate and low growth rate. By utilizing the high nucleation rate and low growth rate phenomenon, we have synthesized various kinds of metastable phases which change from nanocrystalline base structure to bulk glassy base structure through an amorphous base structure with increasing quenching effect (cooling rate). It is also known that the quenching effect is dominated by cooling rate from melt resulting from rapid solidification processes as well as by supercooling capacity of alloy liquid depending on alloy component and composition.When we focus on the strengthening caused by metastable phases, the effect is due to the combination of solid solution + ultra-high density of defects for amorphous phase and dispersion + grain size refinement + segregation for nanocrystalline phase. The amorphous plus nanocrystalline mixed phase alloys are expected to have simultaneously almost all the strengthening mechanisms. By utilizing the combined strengthening mechanisms of these metastable phases, we have tried to prepare novel Al-based alloys with the high tensile strength exceeding 1500 MPa at room temperature, high elevated temperature strength above 500 MPa at 573 K, high rotating beam fatigue strength above 400 MPa at 10 7 cycles, high elevated temperature fatigue strength above 100 MPa at 673 K after 10 6 cycles and high corrosion resistance below 20 mm/year in 0.25 M NaOH aqueous solution at 293 K. In addition, these Al-based alloys have been requested to exhibit a low wear loss, low coefficient of thermal expansion and low material density etc. This paper presents the review of the development achievements of metastable Al-based alloys obtained in our group on the basis of the above-described backgrounds and objectives. This paper reviews the features of alloy components, structure and mechanical properties, p...

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“…This method has been used to develop nanocrystalline materials in several interesting alloy categories that include the soft magnetic alloys, 2,5,6) hard magnetic alloys, 7,8) and high strength aluminum alloys. 9) In particular, while the strength of amorphous aluminum alloys has been reported to exhibit levels up to 1000 MPa, 10) alloys that undergo partial crystallization, resulting in the formation of a distribution of nano-sized crystals, have shown strengths up to 1500 MPa. 11) Since the strength of the partially crystallized alloys are found to depend on precipitate size and volume fraction, understanding and controlling the mechanisms that determine the formation of primary aluminum is of central interest.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystallization Reactions in Amorphous Aluminum Alloys

et al. 2003

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Primary crystallization is the key reaction that controls the synthesis of nanostructured bulk volumes comprised of a high density (10 21 -10 23 m À3 ) of nanocrystals (7-20 nm) within an amorphous matrix. The primary crystallization kinetics in response to the annealing and the deformation of amorphous Al alloys are assessed in specific sample types and selected thermal treatments to evaluate primary nanocrystallization reactions. All amorphous Al alloy compositions are hypereutectic so that the initial phase selection of primary Al proceeds at a reduced driving free energy compared to thermodynamically favored intermetallic phases. Differential scanning calorimetry (DSC) studies on powders and melt spun ribbon (MSR) samples based upon thermal cycling and annealing below the glass transition, T g , demonstrate a strong sensitivity of the primary crystallization onset and reaction enthalpy to thermal history and the as-quenched state. Microcalorimetry investigations and careful analysis of nanocrystal size distributions for Al 92 Sm 8 MSRs following sub-T g anneals reveal a partial nanocrystallization reaction resulting from a transient, decaying nucleation rate and a limited supply of heterogeneous nucleation sites. While crystallization is generally thought of as a thermally activated process, it can also be induced in response to external forcing such as irradiation or mechanical alloying. Intense deformation of amorphous Al 88 Y 7 Fe 5 MSR, for example, yields a distribution of Al-nanocrystallites in the amorphous matrix without thermal annealing. Moreover, the results of cold-rolling experiments with melt-spun amorphous Al 85 Ni 10 Ce 5 ribbons show that the deformation process can alter the phase selection upon annealing. These results suggest that the shear process during rolling effects a local rearrangement of atoms in the amorphous matrix. The kinetics behavior highlights the important role of the as-synthesized amorphous structure, reaction pathways and transient conditions on the evolution of nanoscale microstructures during primary crystallization.

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Aluminum-Based Amorphous Alloys with Tensile Strength above 980 MPa (100 kg/mm²)

Cited by 379 publications

References 14 publications

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Development and Applications of Highly Functional Al-based Materials by Use of Metastable Phases

Nanocrystallization Reactions in Amorphous Aluminum Alloys

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Aluminum-Based Amorphous Alloys with Tensile Strength above 980 MPa (100 kg/mm2)

Cited by 379 publications

References 14 publications

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

Development and Applications of Highly Functional Al-based Materials by Use of Metastable Phases

Nanocrystallization Reactions in Amorphous Aluminum Alloys

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Aluminum-Based Amorphous Alloys with Tensile Strength above 980 MPa (100 kg/mm²)