Formation of a super-saturated solid solution in the AgCu system by mechanical alloying

Uenishi, Koji; Kobayashi, Kojiro F.; Ishihara, Keiichi N.; Shingu, Paul Hideo

doi:10.1016/0921-5093(91)90987-x

Cited by 143 publications

(45 citation statements)

References 5 publications

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“…15,25,26,32,33 This technique offers an alternative to rapidquenching techniques to form metastable alloys of elements which are immiscible under equilibrium conditions. Uenishi et al 18 report that the lattice parameter of bcc and fcc HEBM Cu-Fe alloys increase near linearly with increasing concentration of the dilute element, i.e., Cu in bcc Fe and Fe in fcc Cu, reaching a maximum for Cu 50 Fe 50 . By comparing the lattice parameters measured in HEBM powders to those measured in liquid-quenched ribbons and vapor-quenched thin films, Uenishi et al 18 show the volume expansion is significantly larger in HEBM samples.…”

Section: Miscibility Electronic and Magnetic Properties Of Cu-fementioning

confidence: 99%

“…Uenishi et al 18 report that the lattice parameter of bcc and fcc HEBM Cu-Fe alloys increase near linearly with increasing concentration of the dilute element, i.e., Cu in bcc Fe and Fe in fcc Cu, reaching a maximum for Cu 50 Fe 50 . By comparing the lattice parameters measured in HEBM powders to those measured in liquid-quenched ribbons and vapor-quenched thin films, Uenishi et al 18 show the volume expansion is significantly larger in HEBM samples. From this it is clear that the HEBM samples have a local structure which must differ from those alloys produced by quenching techniques.…”

Section: Miscibility Electronic and Magnetic Properties Of Cu-fementioning

confidence: 99%

“…However, recently HEBM has been reported to form metastable alloys, or more correctly supersaturated solid solutions, of combinations of elements which do not exhibit appreciable solubility in their equilibrium phase diagrams. [15][16][17][18][19][20][21] The alloying phenomenon in these materials has been explained by Yavari, Desre, and Benameur 15 to arise when small fragments, created by codeformation, obtain a critical tip radii, whereupon capillary forces bring about the dissolution of the tip region. Subsequently, the solute content changes within the local spinode increasing the critical radius causing the more rapid dissolution of the region and the eventual complete mixing of one component into the other.…”

Section: Introductionmentioning

confidence: 99%

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Near-neighbor mixing and bond dilation in mechanically alloyed Cu-Fe

et al. 1996

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Extended x-ray-absorption fine-structure ͑EXAFS͒ measurements were used to obtain element-specific, structural, and chemical information of the local environments around Cu and Fe atoms in high-energy ballmilled Cu x Fe 1Ϫx samples ͑xϭ0.50 and 0.70͒. Analysis of the EXAFS data shows both Fe and Cu atoms reside in face-centered-cubic sites where the first coordination sphere consists of a mixture of Fe and Cu atoms in a ratio which reflects the as-prepared stoichiometry. The measured bond distances indicate a dilation in the bonds between unlike neighbors which accounts for the lattice expansion measured by x-ray diffraction. These results indicate that metastable alloys having a positive heat of mixing can be prepared via the high-energy ballmilling process. ͓S0163-1829͑96͒10033-3͔

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Section: Miscibility Electronic and Magnetic Properties Of Cu-fementioning

confidence: 99%

Section: Miscibility Electronic and Magnetic Properties Of Cu-fementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Near-neighbor mixing and bond dilation in mechanically alloyed Cu-Fe

et al. 1996

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“…However, the drawback of these materials is that they can be produced only as deposited thin films or as thin ribbons, which does not permit their direct technical use. Although it is known that supersaturated alloys can also be produced by high energy ball milling 7 , until now the powder metallurgical way to corrosion resistant supersaturated aluminum alloys has not been examined. Therefore the aim of this paper is to study high energy ball milling, compaction and sintering heat treatment as a possible production way for bulk supersaturated Al-Mo alloys with better resistance to localized corrosion.…”

Section: Introductionmentioning

confidence: 99%

A study of Al-Mo powder processing as a possible way to corrosion resistent aluminum-alloys

et al. 2009

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In the present work, two powders of pure Al and of pure Mo, respectively, have been mixed (composition: Al with 15 at.% Mo) and processed by ball milling. The structural changes of the powder vs. milling time were analyzed by X ray diffraction and by scanning electron microscopy up to a milling time of 100 hours. The pitting potentials of the green and of the sintered alloy were determined in NaCl-solution. Experimental Methods MaterialsThe raw materials used in this work were elementary powders of aluminum and of molybdenum. The aluminum powder from Alcoa had a purity of 99.7% and the following particle size distribution: +100#: 0%, +200#: 0.1%, +325#: 11.5%, -325#: 88.4%, according to the manufacturer's analysis. The molybdenum powder from Aldrich had a purity of 99.9+% and an average particle size <10 µm (-100#). The two powders were mixed before milling and 1 wt.(%) of stearic acid was added as process controlling agent. Milling processMilling was performed in a ball mill type Netzsch Molinex PE5. The mill had a stainless steel rotator and chromium steel balls of 6 mm diameter. The ball to powder weight ratio was 10:1. The mill was water cooled and the chamber was purged with argon during the milling process. Milling was carried out with a velocity of 400 rpm. The milling process was interrupted several times in order to remove a small quantity of powder for analysis.A maximum milling time of 100 hours was considered as convenient. Zdujic et al. 8 reported that after this milling time, with low energy, molybdenum was finely dispersed in the aluminum matrix. IntroductionAluminum alloys are susceptible to pitting corrosion in chloride containing solutions. Massive pitting sets in when a critical potential, the so called pitting potential is reached. Alloying elements can influence this critical potential. However, among the alloying elements contained in technical alloys, only Cu shifts the pitting potential up to about 150 mV to the noble direction, but this is not enough to obtain a substantial improvement of the corrosion resistance. In the nineties researchers produced supersaturated Al alloys, mostly alloyed with transition elements such as Mo, W, Ta, Zr, Nb, Cr, Ni [1][2][3][4] . Also rare earth elements have been added more recently 5 . Since the solubility of these elements in Al is very low, they have to be produced by non-equilibrium methods like PVD, ion-implantation or meltspinning. Electrodeposition from ionic liquids has also been applied for supersaturated aluminum alloys 6 . Shifts of more than 1V were reported for the pitting potential of some alloys in chloride solution 1 . However, the drawback of these materials is that they can be produced only as deposited thin films or as thin ribbons, which does not permit their direct technical use. Although it is known that supersaturated alloys can also be produced by high energy ball milling 7 , until now the powder metallurgical way to corrosion resistant supersaturated aluminum alloys has not been examined. Therefore the aim of this paper is to st...

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“…In other words, the externally imposed randomizing action forces the issue despite the fact that the two species dislike each other. The typical deformation routes used were ball milling of powder mixtures, [3][4][5][6][7][8][9][10][11][12][13] cold rolling of stacked multilayers, 14) extrusion of in situ composites, 15) and high pressure torsion. 16) Studies of deformation-driven alloying overcoming thermodynamic driving forces are motivated not only by the science appeal of this fundamental subject, but also by the unusual properties resulting from the nonequilibrium alloys created.…”

Section: Introductionmentioning

confidence: 99%

Dissolving Equilibrium-Immiscible Elements via Severe Plastic Deformation

2006

MATERIALS TRANSACTIONS

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Severe plastic deformation has the fascinating power of alloying equilibrium-immiscible elements, overriding the thermodynamic driving force (positive heat of mixing) that would dictate phase separation in equilibrium. This article briefly reviews the current understanding of this subject, in terms of experimental evidence for atomic-level alloying and phase selection, and in particular the models proposed to explain the driven intermixing. Outstanding issues that await future research are also discussed.

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Formation of a super-saturated solid solution in the AgCu system by mechanical alloying

Cited by 143 publications

References 5 publications

Near-neighbor mixing and bond dilation in mechanically alloyed Cu-Fe

Near-neighbor mixing and bond dilation in mechanically alloyed Cu-Fe

A study of Al-Mo powder processing as a possible way to corrosion resistent aluminum-alloys

Dissolving Equilibrium-Immiscible Elements via Severe Plastic Deformation

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