Effect of Grain Refinement on the Dendrite Coherency Point during Solidification of the A319 Aluminum Alloy

Malekan, Mehdi; Shabestari, S.G.

doi:10.1007/s11661-009-9978-y

Cited by 70 publications

(27 citation statements)

References 11 publications

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“…Moreover, T N -T DCP increased significantly from 6.7°C for the Sr-modified alloy, to 16.5 and 16.8°C after the addition of Al-3Ti-B and Al-5Ti-B, respectively. In addition, t N -t DCP for the Srmodified was around 79.8 s, which increased to 111.6 s and 112.2 s with the addition of Al-3Ti-B and Al-5Ti-B, respectively, which corresponds to previous studies [19,20]. In other words, the coherency parameters reveal that grain refinement increases the temperature (T N -T DCP ) and time (t N -t DCP ) interval of coherency and can postpone dendrite coherency.…”

Section: Aluminium Phasesupporting

confidence: 88%

“…The influence of different concentrations of individual Al-5Ti-B grain refiners on DCP parameters was reported for an A319 alloy [19]. To assess the effect of the combination of a Sr modifier and Al-Ti-B grain refiners on Al dendrite size, the concept of DCP was used according to the two thermocouple technique.…”

Section: Aluminium Phasementioning

confidence: 99%

“…The difference between nucleation temperature and dendrite coherency temperature (T N -T DCP ) corresponds to the free dendritic growth of primary Al, while after DCP it refers to dendrite thickening, resulting in a fixed dendritic network [19]. DCP is important as it marks the transition from mass feeding to inter-dendritic feeding in the solidification process [22].…”

Section: Aluminium Phasementioning

confidence: 99%

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Evaluation of the effect of grain refiners on the solidification characteristics of an Sr-modified ADC12 die-casting alloy by cooling curve thermal analysis

Farahany

Idris

Ourdjini

et al. 2015

J Therm Anal Calorim

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The influence of grain refinement-with the addition of 6 mass% Al-5Ti-B and 10 mass% Al-3Ti-B master alloys-on the temperature-based parameters of a commercial ADC12 die-casting alloy, modified with 0.04 mass% Sr, was investigated using computer-aided cooling curve thermal analysis. Results show that the addition of grain refiners caused the reaction area of the aluminium dendrite to shift up. With the addition of refiner reagents, the nucleation temperature and growth temperature for the evolution of the primary Al dendrite increased, while the recalescence temperature decreased. The dendrite coherency temperature (T DCP ), time (t DCP ), temperature (T N -T DCP ), and time (t N -t DCP ) interval for dendrite coherency and solid fraction at coherency point increased with the addition of Al-3Ti-B and Al-5Ti-B grain refiners. Nevertheless, the growth temperature of the eutectic aluminium-silicon phase remained at the modified range (563.5-565°C) even after the addition of grain refiners. A grain-refined and modified structure was obtained after the addition of refiners, but no obvious mutual effect was found in terms of the coarsening of grain size or silicon demodification in the range of concentrations used in this study.

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Section: Aluminium Phasesupporting

confidence: 88%

Section: Aluminium Phasementioning

confidence: 99%

Section: Aluminium Phasementioning

confidence: 99%

See 1 more Smart Citation

Evaluation of the effect of grain refiners on the solidification characteristics of an Sr-modified ADC12 die-casting alloy by cooling curve thermal analysis

Farahany

Idris

Ourdjini

et al. 2015

J Therm Anal Calorim

View full text Add to dashboard Cite

show abstract

“…[4,5] This means that, to compensate solidification shrinkage, the melt must flow through the solid network of the dendrites. Casting defects during equiaxed dendritic growth, e.g., macrosegregation, shrinkage, porosity, and hot tearing, start to develop at the point where the dendrites impinge and a continuous network becomes coherent.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cooling Rate on the Dendrite Coherency Point During Solidification of Al2024 Alloy

Ghoncheh

Shabestari

2014

Metall Mater Trans A

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Most research related to dendrite coherency point (DCP) has been done on cast aluminum alloys and at a low cooling rate condition. In this research, the DCP of a wrought aluminum alloy is calculated in the range of high cooling rates used in the direct-chill casting process. The two-thermocouple thermal analysis technique was used to determine the DCP of Al2024 alloy. The aim of this work is to investigate the effect of different cooling rates on the dendrite coherency characteristics of Al2024. The cooling rates used in the present study range from 0.4 to 17.5°C s À1 . Also, the effect of 1.2 wt pct Al-5Ti-1B grain refiner on the DCP was studied. To calculate the solid fraction at dendrite coherency, solid fraction versus time is plotted based on Newtonian technique. The results show that by increasing the cooling rate, both time and temperature of dendrite coherency are decreased. Also, by adding the Al-5Ti-1B master alloy, dendrite coherency temperature is reduced and dendrite impingement is postponed. To reduce casting defects occurring during equiaxed solidification, e.g., macrosegregation, porosities, and hot tearing, these two operations which lead to postpone the transition from mass to interdendritic feeding, or dendrite coherency, can be useful. By increasing the cooling rate, solid fraction at dendrite coherency increases initially and then decreases at higher cooling rates. Presence of grain refiner leads to increasing of solid fraction at DCP. Thus, by delaying the dendrite coherency and increasing the solid fraction at DCP, semi-solid forming can be performed on parts with higher solid fraction and less shrinkage. Microstructural evaluation was carried out to present the correlation between the cooling rate and solid fraction in 2024 aluminum alloy.

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“…They give more details about the range of reactions including the start and end points of them. [31][32][33][34] As shown in Figure 9, five main precipitation regions were detected during the solidification of the LF alloy: one pre-eutectic precipitation, the main eutectic reaction, and three posteutectic precipitations. The types of precipitations and their temperature ranges are given in Table V for each alloy.…”

Section: Solidification Eventsmentioning

confidence: 99%

Investigation of the Effects of Ni, Fe, and Mn on the Formation of Complex Intermetallic Compounds in Al-Si-Cu-Mg-Ni Alloys

Gholizadeh

Shabestari

2011

Metall Mater Trans A

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The aim of this work is to partially substitute Fe and Mn for Ni in the 3HA piston alloy and to study the consequences through microstructural evaluation and the thermal analysis technique. Three types of near-eutectic alloys containing (2.6 wt pct Ni-0.2 wt pct Fe-0.1 wt pct Mn), (1.8 wt pct Ni-0.75 wt pct Fe-0.3 wt pct Mn), and (1 wt pct Ni-1.15 wt pct Fe-0.6 wt pct Mn) were produced, and their solidification was studied at the cooling rate of 0.9 K/s (°C/s) using the computer-aided thermal analysis technique. Optical microscopy and scanning electron microscopy were used to study the microstructure of the samples, and energy dispersive X-ray (EDX) analysis was used to identify the composition of the phases. Also, the quantity of the phases was measured using the image analysis technique. The results show that Ni mainly participates as

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Effect of Grain Refinement on the Dendrite Coherency Point during Solidification of the A319 Aluminum Alloy

Cited by 70 publications

References 11 publications

Evaluation of the effect of grain refiners on the solidification characteristics of an Sr-modified ADC12 die-casting alloy by cooling curve thermal analysis

Evaluation of the effect of grain refiners on the solidification characteristics of an Sr-modified ADC12 die-casting alloy by cooling curve thermal analysis

Effect of Cooling Rate on the Dendrite Coherency Point During Solidification of Al2024 Alloy

Investigation of the Effects of Ni, Fe, and Mn on the Formation of Complex Intermetallic Compounds in Al-Si-Cu-Mg-Ni Alloys

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