In-Situ Investigation of Hot Tearing in Aluminum Alloy AA1050 via Acoustic Emission and Cooling Curve Analysis

Pekguleryuz, Mihriban; Li, X.; Aliravci, Celil A.

doi:10.1007/s11661-009-9806-4

Cited by 19 publications

(16 citation statements)

References 16 publications

(24 reference statements)

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“…Two kinds of experiments are often employed to investigate hot tearing: pilot-scale castings [5,16] and dedicated hot tearing apparatuses. [2,[17][18][19][20][21][22][23] The pilot-scale casting is the most direct approach to achieve goals. However, it is time-consuming and costly.…”

Section: Introductionmentioning

confidence: 99%

Effect of Main Elements (Zn, Mg, and Cu) on Hot Tearing Susceptibility During Direct-Chill Casting of 7xxx Aluminum Alloys

Zhang

Zhao

et al. 2019

Metall Mater Trans A

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New 7xxx aluminum alloys with high alloying contents are being designed, which could induce serious hot tearing defects during direct-chill (DC) casting. Among all factors affecting hot tearing of 7xxx alloys, undoubtedly alloying elements play a significant role. In this study, the effect of main alloying elements (Zn, Mg, and Cu) on hot tearing of grain-refined Al-xZn-yMg-zCu alloys was investigated by a dedicated hot tearing rating apparatus simulating the DC-casting process. It was found that the minimum and maximum hot tearing susceptibilities occur for 4 to 6 and 9 wt pct Zn, respectively, indicating the complicated effect of Zn content. The hot tearing resistance of grain-refined Al-9Zn-yMg-zCu alloys is enhanced with increasing Mg content but is deteriorated with increasing Cu content. This can be attributed to the interaction of the thermal stresses, melt feeding, and final eutectics. The observed tendencies of the main alloying elements on hot tearing were also confirmed for four commercial 7xxx alloys. In addition, both the load value at non-equilibrium solidus and the SKK criterion proposed by Suyitno et al. using measured load developments were found to be good indicators in predicting hot tearing susceptibility. This study can provide a beneficial guide in designing 7xxx alloys considering the potential occurrence of hot cracks beforehand.

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Section: Introductionmentioning

confidence: 99%

Effect of Main Elements (Zn, Mg, and Cu) on Hot Tearing Susceptibility During Direct-Chill Casting of 7xxx Aluminum Alloys

Zhang

Zhao

et al. 2019

Metall Mater Trans A

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“…[14,15,[23][24][25] There is still no general conclusion on the fraction solid at the onset of hot tearing. Further work is needed before such a conclusion can be drawn.…”

Section: Comparison With Reported Fraction Solid At Hot Tearingmentioning

confidence: 99%

“…[23] Acoustic emission was also used to detect the onset of hot tearing, and based on the evolution of the latent heat during solidification instead of the Scheil model, the fraction solid was found to be 0.71 to 0.99 in ring casting of 1050 Al. [25] The load cell has been most frequently used to detect the onset of hot tearing so far, and the corresponding fraction solid has been determined based on the Scheil model. For Al alloys, this includes 0.94 in 713 Al cast in a steel mold preheated to 473 K (200°C).…”

Section: Comparison With Reported Fraction Solid At Hot Tearingmentioning

confidence: 99%

Onset of Hot Tearing in Ternary Mg-Al-Sr Alloy Castings

Cao

Haygood

Kou

2010

Metall Mater Trans A

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Ternary Mg-Al-Sr alloys are the base of a few new creep-resistant, lightweight Mg alloys for automobiles. Hot tearing of Mg-Al-Sr alloys was studied by constrained rod casting (CRC) in a steel mold equipped with a load cell and a thermocouple. The alloys investigated included, in order of decreasing hot tearing susceptibility, Mg-4Al-1.5Sr, Mg-6Al-1.5Sr, Mg-8Al-1.5Sr, and Mg-8Al-3Sr. Two different molds were used, one for 8.7-mm-diameter rods and the other 7.9 mm. The cooling rate was varied by varying mold preheating from 523 K (250°C) to 658 K (385°C) and mold insulation. The load curve showed a clear peak when hot tearing occurred in all but Mg-8Al-3Sr due to its high resistance to hot tearing. From the peak and the cooling curve, the temperature at which hot tearing occurred was determined and found to decrease with increasing Al content from 4 to 8 pct. For a specific alloy, the hot tearing onset temperature did not change significantly with the rod diameter or mold preheating, at least within the experimental conditions used. The Scheil solidification model was used to estimate the fraction solid at the onset of hot tearing. It was found that hot tearing occurred near the end of primary solidification L fi a (Mg) and that the fraction solid at which hot tearing occurred decreased with increasing Al content. The validity of the Scheil model was discussed.

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“…Therefore, the Al-Si alloys cannot be used for producing highstrength structural materials with good toughness. However, castings with excellent mechanical properties obtained by modifications of wrought aluminum alloys have recently attracted significant interest [5,6] . Compared to other cast alloys, the Al wrought alloys characterized by high melting temperatures, low fluidity, and extensive solidification ranges, which easily produce various defects, such as hot tears, and result in shrinkage or the presence of intermixed gases.…”

Section: Introductionmentioning

confidence: 99%