Muon diffusion and trapping in aluminum and dilute aluminum alloys: Experiments and comparison with small-polaron theory

Kehr, K. W.; Richter, D.; Welter, J. M.; Hartmann, O.; Karlsson, E.; Norlin, L. O.; Niinikoski, T.; Yaouanc, A.

doi:10.1103/physrevb.26.567

Cited by 122 publications

(31 citation statements)

References 43 publications

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“…1(c) and 1(d) with the binary alloys stored at room temperature suggest rather interesting aspects of muon kinetics with Mg and Si elements: 1) from the spectra at 20 K it is clear that the dissolved Mg in Al well trapped muons, but Si did not. This result is consistent with the previous reports; low temperature depolarization rates depend on impurity elements [10,11]. 2) From the spectra at 300 K there remained deep potentials in 0.5Mg-13d, probably associated with Mg-vacancy clusters trapping muons, but such potentials disappeared in the 0.5Si-12d sample; i.e.…”

Section: Resultssupporting

confidence: 82%

“…Muons have been known to diffuse very fast in pure Al; hence quite dilute (several tens of ppm) impurities, such Mg, Mn, Cu, Ag, etc., produce significant influence on the muon trapping, and thus spin depolarization. The observed temperature variations of depolarization rates of muon spins in Al around 1∼100 K were found to be quite sensitive to the concentrations and elements of impurities [10,11].…”

Section: Introductionmentioning

confidence: 96%

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Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Nishimura¹,

Matsuda²,

Komaki³

et al. 2015

Archives of Metallurgy and Materials

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Zero-field muon spin relaxation experiments were carried out with Al-1.6%Mg 2 Si, Al-0.5%Mg, and Al-0.5%Si alloys. Observed relaxation spectra were compared with the calculated relaxation functions based on the Monte Carlo simulation to extract the dipolar width (∆), trapping (ν t ), and detrapping rates (ν d ), with the initially trapped muon fraction (P 0 ). The fitting analysis has elucidated that the muon trapping rates depended on the heat treatment and solute concentrations. The dissolved Mg in Al dominated the ν t at lower temperatures below 120 K, therefore the similar temperature variations of ν t were observed with the samples mixed with Mg. The ν t around 200 K remarkably reflected the heat treatment effect on the samples, and the largest ν t value was found with the sample annealed at 100 • C among Al-1.6%Mg 2 Si alloys. The as-quenched Al-0.5%Si sample showed significant ν t values between 80 and 280 K relating with Si-vacancy clusters, but such clusters disappeared with the natural aged Al-0.5%Si sample.Keywords: Al-Mg-Si alloys, muon spin relaxation, vacancy Stopy Al-1,6%Mg 2 Si, Al-0,5%Mg i Al-0,5%S poddano badaniu relaksacji spinowej mionów w zerowym polu magnetycznym. Obserwowane widma relaksacyjne porównano z funkcjami relaksacji obliczonymi przy wykorzystaniu symulacji Monte Carlo w celu otrzymania informacji o szerokości dipolarnej ∆ (ang. dipolar width) oraz szybkości uwięzienia ν t (ang. trapping) i uwolnienia ν d (ang. detrapping) z pierwotnie związaną frakcją mionów (P 0 ). Z przeprowadzonej analizy wynika, że szybkość uwięzienia mionów zależy od zastosowanej uprzednio obróbki cieplnej oraz stężenia pierwiastków domieszki. W przypadku Mg rozpuszczonego w osnowie Al dominowała szybkość ν t w temperaturach poniżej 120 K, dlatego też w próbkach domieszkowanych Mg obserwowano podobne odchylenia temperaturowe szybkości ν t . Szybkość ν t w temperaturze około 200 K doskonale ukazuje wpływ zastosowanej obróbki cieplnej na omawiane próbki, z których najwyższą wartość ν t wykazały te wyżarzane w 100 • C spośród stopów Al-1,6%Mg 2 Si. Próbka Al-0,5%Si wykazała znaczące wartości ν t pomiędzy temperaturami 80 a 280 K wskazujące na aglomeracje wakancji Si, które jednak zanikają po naturalnym starzeniu stopu Al-0.5%Si.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 96%

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Nishimura¹,

Matsuda²,

Komaki³

et al. 2015

Archives of Metallurgy and Materials

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“…Muon diffusion in Al has been shown to be very fast, even at temperatures below 1 K. 8 We can therefore assume that motional narrowing makes the spin relaxation negligible for muons in a free (non-trapped) state. This makes the muon diffusion rate ν superfluous as a simulation parameter.…”

Section: Data Analysis and Simulationsmentioning

confidence: 99%

“…The methods have been proven very sensitive to point defects such as trace element atoms. 8,10 The property of muons known as asymmetric decay is central to how the measurements are conducted: Muons are unstable, and decay to positrons, whose directions of motion tend to be parallel to the muon spin. The detection of these positrons enables us to follow the time evolution of the average muon polarization inside the material.…”

Section: Introductionmentioning

confidence: 99%

“…5,6 Most of the research activity using muons on aluminium and other pure metals took place in the late 1970s and early 1980s. [7][8][9] In non-magnetic materials, polarized positive muons (µ + ) can be used as probes for atomic-scale magnetic fields. The methods have been proven very sensitive to point defects such as trace element atoms.…”

Section: Introductionmentioning

confidence: 99%

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Probing defects in Al-Mg-Si alloys using muon spin relaxation

et al. 2012

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Muon spin methods are very sensitive to nanoscale defects such as trace elements and vacancies in metals. This sensitivity is required when investigating Al-Mg-Si alloys, a complicated system in which diffusion-controlled phase transformations are responsible for the most important hardening mechanisms. We present muon spin relaxation experiments conducted on Al-Mg-Si alloys at measurement temperatures in the range 20-300 K. Varying the alloy composition and heat treatment, we find differences in muon depolarization in several temperature regimes. This reflects differences in concentration of several types of muon-trapping defects. We identify free solute atom and vacancy regimes, and confirm that the concentration of these defects decrease when an alloy is annealed at low temperature. We further attribute one regime to Mg-Si-vacancy clustering, a mechanism required for precipitation hardening during aging. After storage at room temperature, muon trapping in this regime is more pronounced for a Mg-rich alloy than a Mg-Si-balanced alloy.

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Muon Spin Relaxation and Positron Annihilation Spectroscopy Studies of Natural Aging in Al–Mg–Si Alloys

Wenner

Matsuda

Nishimura

et al. 2012

ICAA13: 13th International Conference on Aluminum Alloys

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Muon spin relaxation (µSR) is sensitive to magnetic fields from atomic nuclei, making it suitable for studying vacancies and solute clustering inside aluminium alloys. Positron annihilation spectroscopy (PAS) gives complimentary information about the electron density. We have conducted µSR and PAS experiments on an Al alloy with 1.07 at.% Mg and 0.53 at.% Si during natural aging after solution heat treatment. Three stages of positron lifetime change are visible, while the muon depolarization shows a decrease through the first two of these. This is explained on the basis of vacancy migration, vacancy-solute binding and solute clustering.

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Muon diffusion and trapping in aluminum and dilute aluminum alloys: Experiments and comparison with small-polaron theory

Cited by 122 publications

References 43 publications

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Probing defects in Al-Mg-Si alloys using muon spin relaxation

Muon Spin Relaxation and Positron Annihilation Spectroscopy Studies of Natural Aging in Al–Mg–Si Alloys

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