Hot tearing mechanisms of B206 aluminum–copper alloy

D’Elia, F.; Ravindran, C.; Sediako, D.; Kainer, Karl Ulrich; Hort, Norbert

doi:10.1016/j.matdes.2014.07.024

Cited by 55 publications

(35 citation statements)

References 21 publications

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“…Lee et al [24] investigated the effect of temperature and strain rate experimentally on the dynamic impact properties of 7075 Aluminum alloy and concluded that the compressive stress-strain response of the material is affected by temperature and strain rate. Elia et al [25] reported that cooling rate has a tremendous impact on the grain refinement of B-206 Al-Cu alloys. Therefore, temperature and strain rate dependencies should be studied to depict the mechanical properties of Al-Cu nanostructures too.…”

Section: Introductionmentioning

confidence: 99%

Atomistic study of hardening mechanism in Al-Cu nanostructure

2019

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Nanostructures have the immense potential to supplant the traditional metallic structure as they show enhanced mechanical properties through strain hardening. In this paper, the effect of grain size on the hardening mechanism of Al-Cu nanostructure is elucidated by molecular dynamics simulation. Al-Cu (50-54% Cu by weight) nanostructure having an average grain size of 4.57 to 7.26 nm are investigated for tensile simulation at different strain rate using embedded atom method (EAM) potential at a temperature of 50~500K. It is found that the failure mechanism of the nanostructure is governed by the temperature, grain size as well as strain rate effect. At the high temperature of 300-500K, the failure strength of Al-Cu nanostructure increases with the decrease of average grain size following Hall-Petch relation. Dislocation motions are hindered significantly when the grain size is decreased which play a vital role on the hardening of the nanostructure. The failure is always found to initiate at a particular Al grain due to its weak link and propagates through grain boundary (GB) sliding, diffusion, dislocation nucleation and propagation. We also visualize the dislocation density at different grain size to show how the dislocation affects the material properties at the nanoscale. These results will further aid investigation on the deformation mechanism of nanostructure.

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Section: Introductionmentioning

confidence: 99%

Atomistic study of hardening mechanism in Al-Cu nanostructure

2019

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“…The key factors for hot tearing are liquid film and inadequate eutectic feeding in the last stage of solidification, together with thermally induced stress-strain, which cannot be accommodated by the semi-solid material. [1,[4][5][6][7] Hot tearing susceptibility (HTS) is highly dependent on the chemical compositions of Al alloys, and is described as a lambda curve for binary alloys. In most binary alloys, an initial increase in solute content (start of the lambda curve) enlarges the solidification interval.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, it is believed that grain refining increases the hot tearing resistance by reducing the grain size, altering the grain morphology from columnar to equiaxed, and decreasing the film thickness between the grains. [1,5,7] However, Easton et al [6] state that refined grain size reduces the permeability of the mush and enhances the hot tearing tendency. [1,6] Besides the chemical composition, process variables such as mold and melt temperature [1] and melt quality [8] affect the HTS.…”

Section: Introductionmentioning

confidence: 99%

“…[2] As previously mentioned, industrial experience shows that new modifications of AA 3000 alloys with Cu and small additions of Ti and Zr cause strong hot tearing sensitivity. Hot tearing has been intensively studied for AA2000, AA6000, and AA7000 alloys, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] while only limited data are available for AA3000 alloys. [17,18] This shows that more studies on hot tearing formation for the AA3xxx group are needed.…”

Section: Introductionmentioning

confidence: 99%

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Hot Tearing Susceptibility of AA3000 Aluminum Alloy Containing Cu, Ti, and Zr

Razaz

Carlberg

2019

Metall Mater Trans A

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Severe hot tearing has been observed during DC casting of modified AA3000 alloys with additions of Cu, Ti, and Zr, although these alloys are regarded as rather easy to cast. Extensive studies have been performed on both synthetic and industrial AA2000, AA6000, and AA7000 alloys, but less data are available for AA3000 alloys. This work was thus initiated to investigate the hot tearing susceptibility of AA3000 alloys with varying alloy element content using constrained rod casting molds. The results showed that the Cu and Fe content have a major impact on hot tearing resistance, while the effects of Zr and Ti are minor. Cu in a range from 0.3 to 1.2 wt pct significantly increased the hot tearing tendency. This is due to the existence of high eutectic fractions at low temperatures, as well as porosity formation associated with bad feeding at the end of solidification. A strong cracking tendency was observed below an Fe content 0.2 wt pct owing to decreased precipitation of the Al 6 (Mn, Fe) phase. It was found that primary Al 6 (Mn, Fe) phases lead to early bridging between the grains, which reinforces the alloy during the vulnerable temperature range for hot tearing. Zr and Ti additions weakly enhanced or reduced hot tearing severity, respectively.

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“…In addition, they have a promising high temperature tensile strength [34]. However, 206 cast alloys are susceptible to hot tearing during the casting process [35,36]. Iron is one of the most common impurities in aluminum alloys.…”

Section: Introductionmentioning

confidence: 99%

Effects of Iron-Rich Intermetallics and Grain Structure on Semisolid Tensile Properties of Al-Cu 206 Cast Alloys near Solidus Temperature

Bolouri

Liu

Chen

2016

Metall Mater Trans A

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The effects of iron-rich intermetallics and grain size on the semisolid tensile properties of Al-Cu 206 cast alloys near the solidus were evaluated in relation to the mush microstructure.Analyses of the stress-displacement curves showed that the damage expanded faster in the mush structure dominated by plate-like β-Fe compared to the mush structure dominated by Chinese script-like α-Fe. While there was no evidence of void formation on the β-Fe intermetallics, they blocked the interdendritic liquid channels and thus hindered liquid flow and feeding during semisolid deformation. In contrast, the interdendritic liquid flows more freely within the mush structure containing α-Fe. The tensile properties of the alloy containing α-Fe are generally higher than those containing β-Fe over the crucial liquid fraction range of ~0.6 to 2.8%, indicating that the latter alloy may be more susceptible to stress-related casting defects such as hot tearing. A comparison of the semisolid tensile properties of the alloy containing α-Fe with different grain sizes showed that the maximum stress and elongation of the alloy with finer grains were moderately higher for the liquid fractions of ~2.2-3.6%. The application of semisolid tensile properties for the evaluation of the hot tearing susceptibility of experimental alloys is discussed.2

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Hot tearing mechanisms of B206 aluminum–copper alloy

Cited by 55 publications

References 21 publications

Atomistic study of hardening mechanism in Al-Cu nanostructure

Atomistic study of hardening mechanism in Al-Cu nanostructure

Hot Tearing Susceptibility of AA3000 Aluminum Alloy Containing Cu, Ti, and Zr

Effects of Iron-Rich Intermetallics and Grain Structure on Semisolid Tensile Properties of Al-Cu 206 Cast Alloys near Solidus Temperature

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