Relationship between formability and cast structures in end-chill directionally solidified Al–Cu alloys

Taha, M. A.; El‐Mahallawy, N. A.; Hamouda, Rawia M.

doi:10.1016/s0261-3069(01)00058-9

Cited by 14 publications

(2 citation statements)

References 3 publications

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“…Michael and Bever [2] report that with increasing cooling rate, the amount of NEE increases as expected. The same tendency was observed by Taha et al [3] and Sarreal and Abbaschian, [4] who found the amount of NEE to increase monotonically up to a cooling rate of 190 K/s, followed by a strongly reduced fraction of NEE at 1700 K/s (the value given for 37,000 K/s was taken from a sample that has a different gross composition). They interpret the ''maximum'' as a result of back diffusion, dendrite tip undercooling, and eutectic temperature depression.…”

Section: Introductionsupporting

confidence: 79%

Microsegregation during Solidification of an Al-Cu Binary Alloy at Largely Different Cooling Rates (0.01 to 20,000 K/s): Modeling and Experimental Study

Kasperovich¹,

Volkmann²,

Ratke³

et al. 2008

Metall Mater Trans A

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Microsegregation in the Al 4 wt pct Cu alloy was investigated experimentally in a large range of cooling rates from 0.01 to 20,000 K/s using different solidification techniques. The microstructure was modeled using two-dimensional (2-D) pseudo-front tracking (PFT) developed by Jacot and co-workers. The experimentally determined amount of nonequilibrium eutectics increases with the cooling rate in the range 0.01 to 3 K/s and then decreases in the range 20 to 20,000 K/s. The fraction of eutectic calculated from the 2-D PFT model shows not only the same tendency, but also agrees quantitatively very well with the experiments over the range of cooling rates. It can also be explained qualitatively how the observed in terms of coarsening of the secondary dendrite arms and the back diffusion in the way both depend on the local solidification time.

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Section: Introductionsupporting

confidence: 79%

Microsegregation during Solidification of an Al-Cu Binary Alloy at Largely Different Cooling Rates (0.01 to 20,000 K/s): Modeling and Experimental Study

Kasperovich¹,

Volkmann²,

Ratke³

et al. 2008

Metall Mater Trans A

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“…One group of scientists performed extensive examination of end-chill directional solidification of Al-Cu alloys and reported the following effects of a higher melt superheat (50 to 200 K): a higher heat-transfer coefficient in the liquid state, a smaller air gap, a longer local solidification time, a larger columnar-grain zone, and faster growth of columnar grains. [10,11,12] Contrasting results are given by Ferreira et al [13] for upward unidirectional solidification of an Al-6.2 pct Cu alloy superheated by 20 to 110 K. They claim that the heat-transfer coefficient between the molten metal and the mold decreases with increasing melt temperature. As a result of the correspondingly slower solidification, the mushy zone becomes thicker and the inverse macrosegregation more severe.…”

Section: Introductionmentioning

confidence: 89%

Effects of melt temperature and casting speed on the structure and defect formation during direct-chill casting of an Al-Cu alloy

Eskin¹,

Savran²,

Katgerman

2005

Metall Mater Trans A

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A thorough experimental investigation of the effects of melt temperature and casting speed on the structure and defect formation during the steady and nonsteady stages of direct-chill (DC) casting of an Al-2.8 pct Cu alloy is performed. In addition, the temperature and melt-flow distributions in the sump of billets cast at different melt temperatures are numerically simulated and used in the discussion on the experimental results. Apart from already known phenomena such as the coarsening of the structure, deepening of the sump, and increased probability of bleed-outs during DC casting with increased casting temperature, a few new observations are made. The increased melt temperature is shown to increase the severity of subsurface segregation, whereas the macrosegregation in the rest of the billet remains virtually unaffected. Hot-tearing susceptibility is strongly diminished by an increased melt superheat. The amount and distribution of "floating" grains is demonstrated to depend on both the melt temperature and the casting speed. The porosity was found to only slightly depend on the melt temperature. The amount of nonequilibrium eutectic in the center of the billet increases with increasing melt temperature. The effects of melt temperature on the dimensions of the sump, transition region, and mushy zone and on the melt-flow pattern in the sump are discussed and used in the interpretation of experimentally observed phenomena.

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Variations of Microsegregation and Second Phase Fraction of Binary Mg-Al Alloys with Solidification Parameters

Paliwal

Kang

Essadiqi

et al. 2014

Metall Mater Trans A

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Relationship between formability and cast structures in end-chill directionally solidified Al–Cu alloys

Cited by 14 publications

References 3 publications

Microsegregation during Solidification of an Al-Cu Binary Alloy at Largely Different Cooling Rates (0.01 to 20,000 K/s): Modeling and Experimental Study

Microsegregation during Solidification of an Al-Cu Binary Alloy at Largely Different Cooling Rates (0.01 to 20,000 K/s): Modeling and Experimental Study

Effects of melt temperature and casting speed on the structure and defect formation during direct-chill casting of an Al-Cu alloy

Variations of Microsegregation and Second Phase Fraction of Binary Mg-Al Alloys with Solidification Parameters

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