Quenched-in Vacancies in Aluminium

Furukawa, Kozo; Takamura, Jin-ichi; Kuwana, Nobuo; Abe, Mutsumi

doi:10.1143/jpsj.41.1584

Cited by 37 publications

(3 citation statements)

References 15 publications

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“…Kimura, Kimura and Hasiguti(6) calculated B1 to be 0.2eV, assuming the formation energy of a vacancy in pure aluminum to be 0.76eV. Recent quenching experiments give the formation energy to be 0.70eV (7). If a smaller value is taken for the formation energy, the resulting binding energy B1 will be smaller.…”

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A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys

Kimura

Hasiguti

1975

Trans. JIM

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A general treatment to calculate the concentration of vacancy-solute atom pairs in a ternary dilute solid solution is presented. This treatment is applicable to a wide range of vacancy concentration relative to the concentration of one kind of solute atoms. The treatment is applied to explain the effect of tin addition on the rates of low temperature aging in Al-Cu alloys. The difference in the activation energy for aging between Al-Cu alloys and an Al-Cu-Sn alloy is analyzed to find the binding energy of a vacancy-tin atom pair to be about 0.3eV larger than that of a vacancy-copper atom pair. The experimental result that the retardation of aging due to tin addition is appreciable only for tin concentrations larger than the vacancy concentration is also explained satisfactorily.

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A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys

Kimura

Hasiguti

1975

Trans. JIM

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“…The annealing at 350 C and the successive furnace-cooling removes excess vacancies, secondary defects and strains on and after the quenching; this annealed-out condition was adopted as a reference of the resistivity of the specimen. Normalization by dividing by R A can cancel out the effect of change in the size factor 19) of the specimen. For magnesium, the oxidation and sublimation of the surface are particularly worrisome.…”

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Effects of Hydrogen on the Vacancy Formation in Magnesium

2008

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Quenching and annealing experiments with electrical resistivity measurements were applied to magnesium to investigate the formation of thermal vacancies. Two specimens made from materials differing in impurity contents were examined. One of the specimens quenched in a methanol bath at À80C from elevated temperatures ranging from 160 C to 500 C revealed a significant decrease in electrical resistance after annealing for 10 min in the bath. Based on the annealing behaviors at low temperatures (À100 C to À60 C) after the quenching from 200 C, this decrease is thought to be due to the presence of hydrogen in solution. The other specimen, presumably containing smaller amounts of hydrogen, was quenched in iced water from elevated temperatures (200 C-560 C) which yielded results characterized by two thermal activation processes. These processes had the activation energies 54.1 kJ/mol (0.56 eV) and 89.8 kJ/mol (0.93 eV) for the lower and higher quenching temperature ranges, respectively. The former is ascribed to the formation energy of a vacancy interacting with hydrogen and the latter to the intrinsic formation energy of a vacancy. The difference between these energies, 35.7 kJ/mol (0.37 eV), is the binding energy between a vacancy and a hydrogen atom.

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“…Figure 3 shows d q corrected by 4t 1 /2 (nV m) with a magni® ed scale for the time axis up to 6 h in ® gure 2. The saturated value of d q is about 45 nV m. The equilibrium concentration of vacancies at 320 ë C is about 6´10 -6 in fractional terms, and the contribution to the resistivity increase is about 66 nV m using 11 mV m per atomic fraction as the speci® c electrical resistivity of vacancy (Furukawa et al 1976). The saturated value of ® gure 3 is smaller than 66 nV m. However, it should be noted that some of the vacancies were generated before the temperature attained 320 ë C, because the heating rate of this temperature rise was 60 ë C h -1 .…”

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Thermal generation of vacancies in high-quality aluminium crystals

Kino¹

1998

Philosophical Magazine A

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The dislocation density in high-purity (99.9999%) aluminium has been decreased to 10 5 -10 7 m -2 by cyclic annealing. In such a crystal, there are only a few sources for vacancy generation, so that it is expected to take a long time to attain the thermal equilibrium concentration of vacancies. In order to study the generation rate of vacancies, the electrical resistance has been measured accurately at high temperatures. It is found that it takes at least several hours to attain the thermal equilibrium concentration. For comparison, generation pro® les from pre-existing dislocations and interstitial-type dislocation loops are estimated with a di usion-limited model. It is concluded that, even in a highquality aluminium crystal, most vacancies are generated from pre-existing dislocations, and only a small fraction is generated by the growth of interstitial-type dislocation loops. The surface oxidizes at a rate of about an atom layer per an hour and is not e ective for the generation of vacancies.Recently, the degree of perfection of crystals has been improved; so it is interesting to know where vacancies are thermally generated in such high-quality crystals. In high-purity (99.9999%) aluminium, the dislocation density can be decreased to 10 6 -10 7 m -2 by cyclic annealing (Deguchi et al. 1977). In such a crystal, there are few sources for vacancy generation, and so small interstitial-type dislocation loops are formed by a temperature rise to around 300 ë C and they grow by emitting vacancies.

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Quenched-in Vacancies in Aluminium

Cited by 37 publications

References 15 publications

A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys

A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys

Effects of Hydrogen on the Vacancy Formation in Magnesium

Thermal generation of vacancies in high-quality aluminium crystals

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Quenched-in Vacancies in Aluminium

Cited by 37 publications

References 15 publications

A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al&ndash;Cu&ndash;Sn Alloys

A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al&ndash;Cu&ndash;Sn Alloys

Effects of Hydrogen on the Vacancy Formation in Magnesium

Thermal generation of vacancies in high-quality aluminium crystals

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A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys

A General Treatment of the Distribution of Vacancies to Solute Atoms in a Ternary Solid Solution and its Application to Low Temperature Aging in Al–Cu–Sn Alloys