Precipitation sequences during quenching of the AA 7010 alloy

Godard, David; Archambault, P.; Aeby‐Gautier, Elisabeth; Lapasset, G.

doi:10.1016/s1359-6454(02)00063-0

Cited by 163 publications

(83 citation statements)

References 12 publications

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“…They provide a thermal stability of dislocation structures 14,15) and prevent any relaxation of strain gradients. It is known that the particles of -phase (Mg(Zn 2 ,AlCu)), S-phase (Al 2 CuMg), T-phase (Al 32 (Mg,Zn) 49 ) and the Al 3 (Zr/Cr) dispersoids are presented in 7475 Al alloy at 673 K. 24) It is clearly seen in Figs. 6 and 7 that many precipitates are located along strain-induced boundaries with high angle misorientation, which are formed faster in the regions containing rich secondary phases particles (Fig.…”

Section: Discussionmentioning

confidence: 95%

Grain Refinement in As-Cast 7475 Aluminum Alloy under Hot Equal-Channel Angular Pressing

et al. 2003

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Microstructural evolution taking place during equal channel angular pressing (ECAP) was studied in an as-cast 0.16%Zr modified 7475 aluminum alloy at a temperature of 673 K. The structural changes are characterized by development of deformation bands due to large strain inhomogeneity occurring through the ECAP die. Repeated deformation leads to an increasing of number and misorientation angle of the boundaries of deformation bands, finally followed by formation of new fine grains at high strains. The misorientation angle distribution for newly developed boundaries shows a single peak type at relatively low misorientations in low strain and changes to a bimodal distribution with two peaks at low and high misorientations in moderate strain. Pressing to a strain of 12 leads to a full development of new grains surrounded by medium to high angle boundaries with an average size of about 1.7 mm. It is concluded that grain refinement occurs by a deformation-induced continuous reaction, that is essentially similar to continuous dynamic recrystallization.

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Section: Discussionmentioning

confidence: 95%

Grain Refinement in As-Cast 7475 Aluminum Alloy under Hot Equal-Channel Angular Pressing

et al. 2003

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“…4) Through the participation of copper into the precipitates, M-phase ranges from MgZn 2 to AlCuMg described as isomorphous Mg(Al,Cu,Zn) 2 , and Tphase ranges from Al 2 Mg 3 Zn 3 to Al 6 CuMg 4 described as isomorphous Mg 3 (Al,Cu,Zn) 2 . 5,11,14,16) S-phase has a relatively fixed composition as Al 2 CuMg. 5,11) The aluminum corner of the Al-Mg-Zn diagram shows that higher Zn:Mg ratio exceeding 2.2 favors MgZn 2 (), and lower Zn:Mg ratio less than 2.2 favors Al 2 Mg 3 Zn 3 (T).…”

Section: Control Of Equilibrium Phases (Mts) In the Modified Aluminmentioning

confidence: 99%

“…Besides the minor phases ( = Al 2 Cu, Z = Mg 2 Zn 11 ), the resulting microstructure is generally characterized by equilibrium phases of soluble M (MgZn 2 = ), T (Al 2 Mg 3 Zn 3 ) and their isomorphous phases, S (Al 2 CuMg), and insoluble Al 7 Cu 2 Fe particles. 4,5,[11][12][13][14][15][16][17] These phases constitute most of the microstructure and govern the general properties. M-phase and its precursors GP zone and intermediate precipitate ( 0 ) are responsible for high strength.…”

Section: Introductionmentioning

confidence: 99%

Control of Equilibrium Phases (M,T,S) in the Modified Aluminum Alloy 7175 for Thick Forging Applications

Lim

Eun²,

Nam

2003

Mater. Trans.

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Microstructural evolutions, especially for the coarse equilibrium phases, M-, T-and S-phase, are investigated in the modified aluminum alloy 7175 during the primary processing of large ingot for thick forging applications. These phases are evolved depending on the constitutional effect, primarily the change of Zn:Mg ratio, and cooling rate following solutionizing. The formation of the S-phase (Al 2 CuMg) is effectively inhibited by higher Zn:Mg ratio rather than higher solutionizing temperature. The formation of M-phase (MgZn 2 ) and T-phase (Al 2 Mg 3 Zn 3 ) is closely related with both constitution of alloying elements and cooling rate. Slow cooling after homogenization promotes the coarse precipitation of the M-and T-phases, but becomes less effective as the Zn:Mg ratio increases. In any case, the alloy with higher Zn:Mg ratio is basically free of both T and S-phases. The stability of these phases is discussed in terms of ternary and quaternary phase diagrams. In addition, the modified alloy, Al-6Zn-2Mg-1.3%Cu, has greatly reduced quench sensitivity through homogeneous precipitation, which is uniquely applicable in 7175 thick forgings.

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“…It is recognised that for quench sensitive alloys, quenching might induce some precipitation [16]. This is enhanced in the case of thick product where the cooling rate at the core of the part is not high enough to get a fully supersaturated solid solution.…”

Section: Quench Induced Precipitationmentioning

confidence: 99%

Internal Stress Generation during Quenching of Thick Heat Treatable Aluminium Alloys

Drezet¹,

Chobaut²,

Schloth³

et al. 2013

EPD Congress 2013

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In the current trend toward thicker aluminium plates, a major concern is the stress build-up during quenching which causes distortions during machining. Indeed, cooling rates are not high enough, especially at the core of such thick plates, to prevent any precipitation and quench induced precipitates lower the hardening potential. Multi-scale modelling is required when predicting macro-scale stresses after quenching for thick heat treatable aluminium components. The reason is the instantaneous strong coupling between phase precipitation at the nano-scale and material hardening due to precipitation or softening owing to solute depletion at the microscale. For thick parts, quenching intensities decrease when going from the skin to the core of the component, thus introducing a gradient of nanostructure and consequently a gradient of mechanical properties. In addition, large thermally induced deformations lead to high macroscale residual stresses although part of them is relaxed by plastic deformation. These stresses have been measured in water quenched thick plates of 7040 and 7449 aluminium alloys using neutron diffraction and layer removal techniques and the results when compared with a thermomechanical finite element model of quenching highlight the influence of precipitation.

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Precipitation sequences during quenching of the AA 7010 alloy

Cited by 163 publications

References 12 publications

Grain Refinement in As-Cast 7475 Aluminum Alloy under Hot Equal-Channel Angular Pressing

Grain Refinement in As-Cast 7475 Aluminum Alloy under Hot Equal-Channel Angular Pressing

Control of Equilibrium Phases (M,T,S) in the Modified Aluminum Alloy 7175 for Thick Forging Applications

Internal Stress Generation during Quenching of Thick Heat Treatable Aluminium Alloys

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