Thermo-kinetic prediction of metastable and stable phase precipitation in Al–Zn–Mg series aluminium alloys during non-isothermal DSC analysis

Lang, Peter; Wójcik, Tomasz; Povoden-Karadeniz, Erwin; Falahati, Ahmad; Kozeschnik, Ernst

doi:10.1016/j.jallcom.2014.04.119

Cited by 59 publications

(21 citation statements)

References 19 publications

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“…One can see two insignificant exothermic processes at temperatures above ∼ 200 • C (labelled as processes C and D). No other thermal effects were observed up to the end of the linear heating at the heating rates of 1, 2, 5, 10 and 30 K min −1 up to 450 • C. The character of these processes agrees very well with DSC results observed in [3,6,8,10]. SEM proved the Zn,Mg-containing eutectic phase at grain boundaries in the MC state of both alloys.…”

Section: Phase Development In the MC Alloys During Isochronal Annealingsupporting

confidence: 84%

“…The commercial Al-Zn-Mg-based alloys (AA7xxx series) have a variety of applications in automotive and aircraft industries due to their high age-hardening response and low density [1][2][3]. They exhibit reasonable solid solution hardening, but mechanical properties of these alloys logically depend on chemical composition, mainly on Zn and Mg content and on the heat treatment of the studied alloys [2,[4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Although controversies and ambiguities exist about the structures and the species of the hardening precipitates, the precipitation sequence in the alloys has thus far been understood, in terms of precipitation and dissolution of the phases the commonly isothermal sequence is used as (e.g. [2][3][4][5][6][7][8]): supersaturated solid solution → Guinier-Preston (GP) zones → semicoherent η -phase → incoherent η-phase (MgZn 2 ). Instead of stable η-phase, the formation of the GP zones and η -phase are proved to be responsible for the peak *Corresponding author: tel.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of phase development in commercial Al-Zn-Mg(-Mn,Fe) alloy with and without Sc,Zr-addition

Vlach¹,

Kodetová²,

Smola³

et al. 2018

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Precipitation reactions of the Al-Zn-Mg(-Mn,Fe)-based alloys with/without Sc,Zr-addition were studied by microhardness and resistivity measurements, and differential scanning calorimetry. Microstructure observation proved the Zn,Mg-containing eutectic phase at grain boundaries. Positron spectroscopy confirmed the presence of Guinier-Preston (GP) zones in the initial state. The changes in resistivity and microhardness curves as well as in heat flow are mainly caused by the formation and/or dissolution of the Guinier-Preston zones and precipitation of the particles from the Al-Zn-Mg system. Formation of the Mn,Fe-containing particles as well as of the η-and T-phase does not influence hardening significantly. The hardening effect above ∼ 300 • C reflects the Sc,Zr-addition. Heat treatment at 300 • C for 60 min and 460 • C for 45 min is insufficient for homogenization of the alloys. The apparent activation energy values were calculated: dissolution of the GP zones (∼ 106 kJ mol −1), formation of the metastable η-phase (∼ 111 kJ mol −1), formation of the stable η-phase (∼ 126 kJ mol −1

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Section: Phase Development In the MC Alloys During Isochronal Annealingsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of phase development in commercial Al-Zn-Mg(-Mn,Fe) alloy with and without Sc,Zr-addition

Vlach¹,

Kodetová²,

Smola³

et al. 2018

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“…Refs. [8,16,17]) particles of the metastable η -phase were observed at comparable tem- peratures both in AlZnMgScZr and AlZnMgCuScZr alloys. The hardening peak in the temperature range of 150-240 • C, as well as the exothermic B effect is associated with a formation of the η -phase.…”

Section: Resultsmentioning

confidence: 90%

Early Stages of Precipitation in Mould-Cast, Cold-Rolled and Heat-Treated Aluminium Alloy AA7075 with Sc,Zr-Addition

et al. 2020

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Precipitation reactions of the commercial Al-Zn-Mg-Cu(-Sc-Zr) alloy in mould-cast, cold-rolled, and heattreated states were characterized by electron microscopy, X-ray diffraction, thermal analysis, microhardness testing, and positron annihilation spectroscopy. The distinct changes in microhardness curves as well as in a heat flow of the alloys studied are mainly caused by dissolution of clusters and precipitation of particles from the Al-Zn-Mg-Cu system. An easier diffusion of Zn, Mg, and Cu atoms along dislocations is responsible for the precipitation of Zn,Mg,Cu-containing particles at lower temperatures compared to the mould-cast alloys The mould-cast and coldrolled alloys contain solute clusters rich in Mg and Zn. Clusters formed in the heat-treated alloys during natural ageing have similar composition but in addition to Mg and Zn contain also Cu. The Cu-concentration increases with increase of period of natural ageing. The mould-cast state after natural ageing contain in addition to solute agglomerates also vacancy clusters formed by agglomeration of thermal vacancies. Addition of Sc and Zr results in a higher hardness above ≈ 270 • C due to a strengthening by Al3(Sc,Zr) particles with a good thermal stability. Sc and Zr have probably no influence on the evolution of solute clusters.

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“…pico se observa un primer termograma En el 50 entre (A) exotérmico -la a 140°C correspondiente de un segundo agrupamiento formación de ZGPII; eventos exotérmicos se sucede entre 155-325°C, el primer pico del triplete (B) corresponde a la formación de η´(Tpico≈207°C), el segundo pico (C) corresponde a la formación de η (Tpico≈233°C) y el tercer pico (D) se asocia a la formación de la fase T (Tpico≈282°C) de equilibrio; entre 335°C y 450°C se presenta un evento endotérmico (E) correspondiente a la disolución de los precipitados de equilibrio, alcanzándose el estado de SSS por encima de los 450°C. Esta descripción del termograma es la comúnmente aceptada según la bibliografía [3,19,20].…”

Section: Resultados Y Discusión -Materials En Estado Sssunclassified

CALORIMETRIC ANALYSIS OF FORMATION/DISSOLUTION OF GUINIER-PRESTON ZONES IN AN Al-Zn-Mg Alloy

Jodra¹,

Cuniberti²

2019

AnAFA

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Se estudia la formación y disolución de conglomerados de soluto, Zonas Guinier-Preston (ZGP), en una aleación Al-Zn-Mg utilizando Calorimetría Diferencial de Barrido y determinaciones de microdureza Vickers. Las ZGPI se forman por envejecimiento a temperatura ambiente, y durante calentamiento continuo ocurre su disolución superpuesta con la formación de ZGPII entre 50°C y 150°C. Mediante un análisis cuantitativo de los termogramas se evaluó la cinética de formación de ZGPI.

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Thermo-kinetic prediction of metastable and stable phase precipitation in Al–Zn–Mg series aluminium alloys during non-isothermal DSC analysis

Cited by 59 publications

References 19 publications

Characterization of phase development in commercial Al-Zn-Mg(-Mn,Fe) alloy with and without Sc,Zr-addition

Characterization of phase development in commercial Al-Zn-Mg(-Mn,Fe) alloy with and without Sc,Zr-addition

Early Stages of Precipitation in Mould-Cast, Cold-Rolled and Heat-Treated Aluminium Alloy AA7075 with Sc,Zr-Addition

CALORIMETRIC ANALYSIS OF FORMATION/DISSOLUTION OF GUINIER-PRESTON ZONES IN AN Al-Zn-Mg Alloy

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