Secondary precipitation during homogenization of Al-Mg-Si alloys: Influence on high temperature flow stress

Österreicher, Johannes A.; Kumar, M. S. Mohan; Schiffl, Andreas; Schwarz, Sabine; Bourret, Gilles R.

doi:10.1016/j.msea.2017.01.074

Cited by 40 publications

(10 citation statements)

References 16 publications

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“…Dispersoids normally form during the heating stage of homogenization treatment in alloys containing Si, Fe and other transition metals, e.g. Mn and Cr [4][5][6][7][8][9] . It has been shown that dispersoids play an important role in the quench sensitivity of 6xxx series alloys as non-hardening Mg-Si phases tend to precipitate on them during cooling 3,10,11 .…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown that dispersoids play an important role in the quench sensitivity of 6xxx series alloys as non-hardening Mg-Si phases tend to precipitate on them during cooling 3,10,11 . Since the formation of dispersoids is relatively complex 5,[12][13][14][15] , careful temperature control is required in order to obtain a homogeneous distribution 4,7,12,13 . The composition, crystal structure and number density of dispersoids strongly depend on the alloy composition.…”

Section: Introductionmentioning

confidence: 99%

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Quench Sensitivity in a Dispersoid-Containing Al-Mg-Si Alloy

Strobel¹,

Easton

Lay³

et al. 2019

Metall Mater Trans A

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The quench sensitivity of a 6xxx series alloy with a high content of dispersoids was studied over a wide range of cooling rate and natural aging time. Positron annihilation lifetime spectroscopy (PALS), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) were used to characterize the clustering and precipitation reactions. The alloy showed significant quench sensitivity after short natural aging (2 min and 30 min), but the quench sensitivity was lower after long natural aging (24 h). The quench sensitivity after the long natural aging can be accounted for by solute loss due to the formation of non-hardening β' precipitates on the dispersoids during cooling from solution treatment. For short natural aging, however, quenched-in vacancies and modifications to the precipitation sequence also have substantial contributions to the quench sensitivity. This work provides new insight into the quench sensitivity of 6xxx series alloys that contain a high dispersoid density.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quench Sensitivity in a Dispersoid-Containing Al-Mg-Si Alloy

Strobel¹,

Easton

Lay³

et al. 2019

Metall Mater Trans A

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“…On the contrary, α‐dispersoids precipitated during homogenization can obstruct the dislocation motion and control the recrystallization, further improving fatigue strength in deformed 6xxx alloys. [ 12–14 ] However, the α‐dispersoids are coarse and lower in density in 6xxx alloy billets subjected to conventional casting, suppressing the advantages of α‐dispersoids in alloy deformation. [ 15,16 ] Current studies focus on the decrease in size and homogeneity of α‐dispersoids by changing the heat treatment conditions and alloy composition.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Refinement and α‐Dispersoid Evolution in Direct‐Chill Cast Al–Mg–Si–Fe Alloy

et al. 2020

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In the industrial production of 6xxx alloys, direct chill (DC) casting is primarily used due to its low cost and high levels of production. However, in conventional DC casting, the 6xxx alloy billet typically has coarse grains and exhibits microstructural inhomogeneity, particularly coarse Fe-containing intermetallics, because of low cooling rate and high Fe impurity. [1-3] To solve these problems, previous work has reported that increasing casting speed (withdrawal speed of billet during DC casting) refined the microstructure and improved the quality of aluminum alloy billets due to increased cooling rates and improved melt flow. [4,5] However, these improvements are limited even if the casting speed rises to 200 mm min À1[4,5] because the cooling rate is limited to 30-40 K s À1. Moreover, Fe acts as a common impurity, forming coarse and brittle Fe-containing intermetallics when Fe levels are higher than 0.2%. Mn addition, [6] severe plastic deformation, [7] melt shearing, [8] and spray forming [9] can relieve its adverse effects, but complexity and high costs restrict their practicality for the industrial production of aluminum alloys. If Fe-containing intermetallics can be effectively refined during DC casting, its adverse effects can be relieved inexpensively in the 6xxx alloy with high Fe levels. However, conventional DC casting cannot effectively refine the Fe-containing intermetallic. [10,11] Therefore, further increases in casting speed and cooling rate are essential for the refinement of Fe-containing intermetallics, grain structures, and improved microstructural inhomogeneity in the industrially produced 6xxx alloy. Until now, the effects of higher casting speed (300 mm min À1) on the grain structure, Fe-containing intermetallics, and microstructural inhomogeneity of 6xxx alloy billets have rarely been investigated. On the contrary, α-dispersoids precipitated during homogenization can obstruct the dislocation motion and control the recrystallization, further improving fatigue strength in deformed 6xxx alloys. [12-14] However, the α-dispersoids are coarse and lower in density in 6xxx alloy billets subjected to conventional casting, suppressing the advantages of α-dispersoids in alloy deformation. [15,16] Current studies focus on the decrease in size and homogeneity of α-dispersoids by changing the heat treatment conditions and alloy composition. [17-19] Regardless, inadequate attention is paid to the effects of as-cast microstructural evolution on the size, morphology, and number density of α-dispersoids. Meanwhile, the air-cooling process after homogenization is considered for the investigation of precipitation behavior of the alloy in industrial production.

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“…The study of real fluid flow is generally difficult to address by complete theoretical methods, due to the special complications caused by a number of disturbing factors such as fluid friction (viscosity), turbulence, driving solid particles, presence of internal heat sources etc. The knowledge of fundamental properties behavior in a system can help us understand the nature of molecular interactions and so we can determine other thermodynamic properties [4], [5], [16], [17]. Temperature and density are factors that affect the treated metals, which have an important influence on the macroscopic mechanical properties and the stability of materials [6], [7].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Analysis of a Hydraulic Drive System. The Influence of the Work Environment on the Performance of the System

2020

IJOMAM

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This paper aims at highlighting the influence of the properties of the working medium used on static and dynamic performance of intelligent hydraulic drive systems. This paper briefly presents the laws and equations commonly used in the theoretical analysis of pressure fluid systems. Basically, we have aimed at providing a review of these equations and concepts required to develop the mathematical model of such a system.

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Secondary precipitation during homogenization of Al-Mg-Si alloys: Influence on high temperature flow stress

Cited by 40 publications

References 16 publications

Quench Sensitivity in a Dispersoid-Containing Al-Mg-Si Alloy

Quench Sensitivity in a Dispersoid-Containing Al-Mg-Si Alloy

Microstructural Refinement and α‐Dispersoid Evolution in Direct‐Chill Cast Al–Mg–Si–Fe Alloy

Theoretical Analysis of a Hydraulic Drive System. The Influence of the Work Environment on the Performance of the System

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