Early Stage Clustering Behavior in Al-Mg-Si Alloys Observed via Time Dependent Magnetization

Nishimura, K.; Matsuda, Kenji; Lei, Qiankun; Namiki, Takahiro; Lee, Seungwon; Nunomra, Norio; Matsuzaki, Takashi; Hutchison, W. D.

doi:10.2320/matertrans.m2015474

Cited by 9 publications

(7 citation statements)

References 26 publications

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“…In stage IV, cluster growth takes place . The latest results on time‐dependent magnetization also indicate Si clustering in early stage II due to the Si‐dependent activation energy of the stage II/III transition . Nevertheless, the role of Si before Mg gets involved is still under debate, because this stage is difficult to access experimentally in Al–Mg–Si–(Cu) alloys.…”

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confidence: 99%

Atom Probe Tomography Study of As‐Quenched Al–Mg–Si Alloys

et al. 2016

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This study deploys a new method to gain insight into the as-quenched microstructure of Al-Mg-Si alloys using atom probe tomography (APT) as an imaging method. Here, diffusion of solutes during sample preparation and handling is suppressed via application of cryogenic temperatures beginning from quenching in liquid nitrogen (LN2) through to APT experiments at 33 K. The solute distribution is studied via customized nearest-neighbor distribution and radial distribution function analysis. The influence of energy input on the solute distribution via cryogenic focused ion beam (FIB) preparation is also shown.

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confidence: 99%

Atom Probe Tomography Study of As‐Quenched Al–Mg–Si Alloys

et al. 2016

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“…The actual ∆ value depends on the atomic arrangement of trapping site of muons and a number density of trapping sites since the muon spin depolarization occurs only when it is trapped; if muon is moving the motional narrowing effect on ∆ happens. [17,18], positron annihilation lifetime spectroscopy [19] and other methods [20]. The stage transition times (tII) became short when the measurement temperatures were raised as indicated by the arrows in Fig.…”

Section: Resultsmentioning

confidence: 99%

Time Dependence of Muon Spin Relaxation Rate in Aluminum and Al-1.6%Mg<sub>2</sub>Si Alloy

Nishimura

Matsuda

Lee

et al. 2020

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Zero-field muon spin relaxation experiments were carried out for Al-1.6%Mg2Si and a pure aluminum in isothermal conditions between 260 and 300 K. Observed relaxation spectra were analyzed to extract the dipole width (D) values which were found to decrease with time after solution heat treatment and quenching. Time variations of D appeared to take place two stages in both samples. The stage transition times (tII) deduced for Al-1.6%Mg2Si were comparable to those for the Si-rich clustering stage reported for Al-Mg-Si alloys. The estimated activation energy of Si-rich clustering was 0.62 (±0.04) eV. The stage transition times (tM) for the pure aluminum were 255, 110 and 82 min after quenching at the measuring temperatures of 260, 280 and 300 K, respectively. An Arrhenius plot of logarithmic tM against reciprocal temperature resulted in an activation energy of 0.19 (±0.06) eV.

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“…The effects are small (≤0.5% variation) but measurable and show a similar pattern as positron lifetimes. Si-rich and Mg-rich clusters are thought to give rise to different magnetisation contributions but the exact mechanisms are not yet known [18,19].…”

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confidence: 99%

Exploring the hidden world of solute atoms, clusters and vacancies in aluminium alloys

Banhart

Yang

et al. 2020

MATEC Web Conf.

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Precipitation hardening involves solutionising, quenching and annealing steps, the latter often at various temperatures. The phenomena observed in Al-Mg-Si alloys are very complicated and partially not well understood. During and after quenching, solute atoms diffuse through the lattice assisted by vacancies and form atom clusters that gradually grow. These act back onto vacancies, which complicates the situation. We apply positron annihilation techniques in addition to traditional hardness, resistivity and thermal measurements to clarify what happens in various stages of thermal treatment: The quenching process can be divided into a stage of vacancy loss and of precipitation. Very short artificial ageing treatments after heating at different rates show that there is a competition between vacancy losses and cluster formation as the temperature increases. The difference between natural ageing and artificial ageing can be defined based on the importance of excess vacancies. Based on such results the behaviour of “invisible” objects such as vacancies and small clusters can be better understood but some open question remain such as the kinetics of secondary ageing or the details of the negative effect of natural ageing on artificial ageing.

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Early Stage Clustering Behavior in Al-Mg-Si Alloys Observed via Time Dependent Magnetization

Cited by 9 publications

References 26 publications

Atom Probe Tomography Study of As‐Quenched Al–Mg–Si Alloys

Atom Probe Tomography Study of As‐Quenched Al–Mg–Si Alloys

Time Dependence of Muon Spin Relaxation Rate in Aluminum and Al-1.6%Mg<sub>2</sub>Si Alloy

Exploring the hidden world of solute atoms, clusters and vacancies in aluminium alloys

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