Tensile Properties and Hot-Tearing Tendencies of 3xxx Alloys

Nordmark, Arne; Ellingsen, Kjerstin; Johansson, Anders; M’Hamdi, M.; Kvithyld, Anne; Marson, Andrew; Azar, Amin S.

doi:10.4028/www.scientific.net/msf.794-796.95

Cited by 3 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Time for coalescence is limited and thus mechanical coherency is delayed. The volume fraction of solid at rigidity determined in the present work agrees with recent studies on tensile coherency [4] and hot tearing [28] in aluminum alloys. The dependence with solidification time is also in accordance with the industrial observation that increasing casting speed during DC casting of aluminum billets and rolling sheets increases drastically the risk of hot tearing.…”

Section: B Determination Of Rigidity Temperature and Solid Volume Frsupporting

confidence: 81%

Measurement of Mechanical Coherency Temperature and Solid Volume Fraction in Al-Zn Alloys Using In Situ X-ray Diffraction During Casting

Drezet

Mireux

Kurtuldu

et al. 2015

Metall Mater Trans A

View full text Add to dashboard Cite

During solidification of metallic alloys, coalescence leads to the formation of solid bridges between grains or grain clusters when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behavior of solidifying alloys and to the prediction of solidification cracking. Coalescence starts at the coherency point when the grains begin to touch each other, but are unable to sustain any tensile loads. It ends up at mechanical coherency when the solid phase is sufficiently coalesced to transmit macroscopic tensile strains and stresses. Temperature at mechanical coherency is a major input parameter in numerical modeling of solidification processes as it defines the point at which thermally induced deformations start to generate internal stresses in a casting. This temperature has been determined for Al-Zn alloys using in situ X-ray diffraction during casting in a dog-bone-shaped mold. This setup allows the sample to build up internal stress naturally as its contraction is prevented. The cooling on both extremities of the mold induces a hot spot at the middle of the sample which is irradiated by X-ray. Diffraction patterns were recorded every 0.5 seconds using a detector covering a 426 9 426 mm 2 area. The change of diffraction angles allowed measuring the general decrease of the lattice parameter of the fcc aluminum phase. At high solid volume fraction, a succession of strain/stress build up and release is explained by the formation of hot tears. Mechanical coherency temperatures, 829 K to 866 K (556°C to 593°C), and solid volume fractions, ca. 98 pct, are shown to depend on solidification time for grain refined Al-6.2 wt pct Zn alloys.

show abstract

Section: B Determination Of Rigidity Temperature and Solid Volume Frsupporting

confidence: 81%

Measurement of Mechanical Coherency Temperature and Solid Volume Fraction in Al-Zn Alloys Using In Situ X-ray Diffraction During Casting

Drezet

Mireux

Kurtuldu

et al. 2015

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…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%

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

Razaz

Carlberg

2019

Metall Mater Trans A

View full text Add to dashboard Cite

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.

show abstract