Microstructure and elevated temperature mechanical properties of a direct-chill cast AA4032 alloy with copper and erbium additions

Chankitmunkong, Suwaree; Eskin, Dmitry; Patakham, Ussadawut; Limmaneevichitr, Chaowalit

doi:10.1016/j.jallcom.2018.12.195

Cited by 16 publications

(12 citation statements)

References 29 publications

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“…The identification of these phases has been done in our previous work. [2] Figure 8 shows the SEM images of the intermetallic particles formed under different casting conditions. The contrast makes it easier to see the b phase (light gray particles).…”

Section: B Refinement Of Fe-containing Intermetallicsmentioning

confidence: 99%

“…These alloys are usually produced into billet by direct-chill (DC) casting for subsequent processing such as extrusion or forging. The mechanical and service properties of these alloys depend on the presence of hard and thermally stable phase particles such as Si, c-Al 7 Cu 4 Ni, d-Al 3 CuNi, b-phase (Al 9 Fe 2 Si 2 ), and Q-Al 5 Cu 2 Mg 8 Si 6 phases [1,2] as well as on the phases that form precipitates upon annealing such as Al 2 Cu and Mg 2 Si. Higher Cu and Ni concentrations are shown to be beneficial for high-temperature properties.…”

Section: Introductionmentioning

confidence: 99%

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Structure Modification upon Ultrasonic Processing of an AA4032 Piston Alloy: Comparison of Permanent Mold and Direct-Chill Casting

Chankitmunkong

Eskin

Limmaneevichitr

2019

Metall Mater Trans A

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Piston Al-Si alloys have very complex compositions and multi-phase heterogeneous structure, so it is necessary to control the formation of primary and eutectic compounds. In this study, the ultrasonic melt processing (USP) of a eutectic Al-Si piston alloy (AA4032-type) was performed in a permanent mold and during direct-chill (DC) casting to study its effects on the structure refinement and modification. The principal difference between these two ways of casting is that in the permanent mold the solidification front progressively moves towards the ultrasound source, while in the DC casting the position of the solidification front is fixed in space. The results showed that the USP can successfully refine primary Si, Fe-containing intermetallics and aluminum grains. Refinement of primary Si was accompanied by the increase in its amount, which was attributed to both enhanced heterogeneous nucleation and fragmentation. The refinement of Fe-containing intermetallics and Al grains resulted from the fragmentation mechanism and were more pronounced when USP was applied below the liquidus temperature in the permanent mold. However, the eutectic phases coarsened upon USP, and this effect was most pronounced when USP was applied to the semi-solid material. This was related to the strong attenuation of acoustic waves, which effectively heats the semi-solid material and induces corresponding coarsening of the phases. Acoustic streaming induced by an oscillating sonotrode affected the depth of the sump while simultaneously decreasing the macrosegregation, which reflects the dominant role of the melt flow directed against natural convection. The results demonstrated the importance of the solidification stage at which the USP was applied and the specifics of the USP mechanisms acting at the different stages of solidification.

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Section: B Refinement Of Fe-containing Intermetallicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure Modification upon Ultrasonic Processing of an AA4032 Piston Alloy: Comparison of Permanent Mold and Direct-Chill Casting

Chankitmunkong

Eskin

Limmaneevichitr

2019

Metall Mater Trans A

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“…[6] In related works, it is shown that the addition of alloying elements (i.e., Mn and Cr [7] or Cu [8,9] ) can increase the complexity of the precipitation sequence during age hardening, which may compromise the hot workability characteristics of the alloy. The mechanical properties of this type of alloy can be significantly improved at elevated temperatures by Er alloying, [10] which was mainly attributed to the presence of Al 3 Er particles. [10][11][12] However, the effects of combined Cu and Er additions on the constitutive parameters and flow behavior of this type of alloy, which includes the constitutive behavior, as well as the work-hardening and softening mechanisms during hot deformation, have not yet been studied.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanical properties of this type of alloy can be significantly improved at elevated temperatures by Er alloying, [10] which was mainly attributed to the presence of Al 3 Er particles. [10][11][12] However, the effects of combined Cu and Er additions on the constitutive parameters and flow behavior of this type of alloy, which includes the constitutive behavior, as well as the work-hardening and softening mechanisms during hot deformation, have not yet been studied. In order to predict the material flow behavior under specific conditions in hot working, constitutive equations are used to describe the flow stress and optimum parameters that can facilitate reliable simulation results of deformation processes.…”

Section: Introductionmentioning

confidence: 99%

“…It was recently shown that a high Cu addition to an AA4032 alloy promoted the formation of primary Si particles through the shift of the eutectic point in the system, while the addition of Er significantly decreased the amount of primary Si and resulted in overall structural refinement. [10] A combined addition of Cu and Er increased the thermal stability of an as-cast alloy at temperatures above 573 K (300°C) through the formation of temperature-resistant phases and structure refinement. [10,11] Moreover, it was reported that the addition of Er to an Al-Si alloy could form precipitates of the Al 3 Er phase, which improved high-temperature strength.…”

Section: Introductionmentioning

confidence: 99%

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Constitutive Behavior of an AA4032 Piston Alloy with Cu and Er Additions upon High-Temperature Compressive Deformation

Chankitmunkong

Eskin

Limmaneevichitr

2019

Metall Mater Trans A

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Aluminum piston alloys of the AA4032 type are produced by direct-chill (DC) casting and subsequent forging; therefore, it is important to understand their thermomechanical behavior. In recent years, it was shown that additions of Cu and Er could improve mechanical properties of these alloys at room and high temperatures. In this work, we studied the constitutive behavior of AA4032-type alloys with and without Cu and Er additions. The experimental true stress-true strain curves were obtained by compression tests under various temperatures [683 K to 723 K (410°C to 450°C)] and strain rates (0.01 to 10 s À1) to determine constitutive parameters [strain-rate sensitivity, activation energy, and Zener-Hollomon (Z) parameter] for the hot deformation behavior of AA4032-type piston alloys with and without additions of Cu and Er. The flow stress decreased with increasing deformation temperature and decreasing strain rate. The results also showed that increasing the Cu content increased the flow stress over the applied range of deformation conditions due to solid-solution strengthening and the formation of primary Si particles, which led to an increase in the activation energy during hot deformation. Moreover, the main microstructural damage in the AA4032 alloy with 3.5 pct Cu was predominantly due to the cracking of primary Si particles. Additions of 0.4 pct Er and 3.5 pct Cu lower the activation energy of deformation, Q, as compared to the base alloy and the alloy with 3.5 pct Cu. The microstructures in the deformed specimens consisted of subgrains, recrystallized grains, and fine eutectic phases. The alloys containing Er demonstrated more polygonized grains at a low strain rate than the alloys without Er, indicating that Er hindered recrystallization development. The peak stress of the AA4032 alloy with 3.5 pct Cu alloy was higher than for the base AA4032 alloy and for the AA4032 alloy with 3.5 pct Cu and 0.4 pct Er additions, which was attributed to the prevalence of the work-hardening mechanism over the softening mechanism.

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Er-containing microalloyed aluminum alloys: a review

Wu,

Sun,

Hong

et al. 2024

J Mater Sci

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Microstructure and elevated temperature mechanical properties of a direct-chill cast AA4032 alloy with copper and erbium additions

Cited by 16 publications

References 29 publications

Structure Modification upon Ultrasonic Processing of an AA4032 Piston Alloy: Comparison of Permanent Mold and Direct-Chill Casting

Structure Modification upon Ultrasonic Processing of an AA4032 Piston Alloy: Comparison of Permanent Mold and Direct-Chill Casting

Constitutive Behavior of an AA4032 Piston Alloy with Cu and Er Additions upon High-Temperature Compressive Deformation

Er-containing microalloyed aluminum alloys: a review

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