Factors affecting thermal contraction behavior of an AA7050 alloy

Zhang, L.; Eskin, Dmitry; Lalpoor, M.; Katgerman, L.

doi:10.1016/j.msea.2010.02.005

Cited by 22 publications

(12 citation statements)

References 7 publications

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“…Note that the measured cooling rates during solidification are between 7 and 12 K/s depending on the thickness of the ceramic fiber materials, which is similar to DC-casting practices. [33] This apparatus provides much information on the load development during solidification and the size of hot cracks of an alloy. Figure 2 displays an example of the load development curve, and the corresponding cooling and solid fraction curves are also shown.…”

Section: B Hot Tearing Rating Apparatusmentioning

confidence: 99%

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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: B Hot Tearing Rating Apparatusmentioning

confidence: 99%

“…The pre-shrinkage expansion occurs firstly mainly due to the evolution of gas. [17,33] As the solidification proceeds, the dendrites begin to impinge. Strong networks start to form and can transfer tensile loads.…”

Section: B Hot Tearing Rating Apparatusmentioning

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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“…However, the high-strength Al alloy ingots with the large size and high content of alloy elements are sensitive to hot tearing and cold cracking [15], so their yields are low. With regard to the Al-Zn-Mg-Cu alloys with a diameter of above 500 mm, the hot tearing is liable to take place above the solidus temperature on account of wide solidification range and low thermal conductivity, while cold cracks frequently occur in a fully solid material because of imposed large thermal gradient [16]. Despite great efforts have been made to avoid these defects, it is still a considerable problem for high-strength Al alloy castings.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical properties of an ultrahigh-strength Al−Zn−Mg−Cu alloy via powder metallurgy and hot extrusion

Chen

Han

et al. 2021

J. Cent. South Univ.

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In this work, a novel ultrahigh-strength Al-10Zn-3.5Mg-1.5Cu alloy was fabricated by powder metallurgy followed by hot extrusion. Investigations on microstructural evolution and mechanical properties of the fabricated samples were carried out. The results show that the grain size of sintered samples matches with the powder particles after ball milling. The relative densities of sintered and hot extruded samples reach 99.1% and 100%, respectively. Owing to the comprehensive mechanism of grain refinement, aging and dispersion strengthening, the ultimate tensile strength, yield strength and elongation of the Al-10Zn-3.5Mg-1.5Cu alloy after hot extrusion and subsequent heat treatment achieve 810 MPa, 770 MPa and 8%, respectively.

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“…Refractory materials are applied in the centre of the mould to reduce the central cross-section temperature gradients and ensure that the solidification fronts encounter each other in the zone in which the temperature is monitored. This device has been widely applied to measure the linear contraction behaviour of different alloying systems, including binary [14,[72][73][74] and commercial [14,26,71,75,76] aluminium alloys (see Section 3.1), although this approach cannot provide information regarding the size of the hot tears and load development during solidification, as shown in Fig. 2.5.…”

Section: Dedicated Hot Tearing Tests Simulating DC Castingmentioning

confidence: 99%

Recent advances in hot tearing during casting of aluminium alloys

Katgerman

et al. 2021

Progress in Materials Science

121

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Hot tearing is one of the most severe and irreversible casting defects for many metallic materials. In 2004, Eskin et al. published a review paper in which the development of hot tearing of aluminium alloys was evaluated . Sixteen years have passed and this domain has undergone considerable development. Nevertheless, an updated systematic description of this field has not been presented. Therefore, this article presents the latest research status of the hot tearing during the casting of aluminium alloys. The first part explains the hot tearing phenomenon and its occurrence mechanism. The second part presents a detailed description and analysis of the characterisation methods of the mushy zone mechanical properties and hot tearing susceptibility. The third part presents considerable data pertaining to the mushy zone behaviour, including those of the linear contraction and load behaviour during solidification, semi-solid strength and ductility, and characteristic points related to hot tearing. The fourth part examines the effect of the composition and casting process parameters on the hot tearing susceptibility of aluminium alloys. The fifth part describes the hot tearing simulations and the associated criteria and mechanisms. Finally, recommendations for the further development of hot tearing research are presented.

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Factors affecting thermal contraction behavior of an AA7050 alloy

Cited by 22 publications

References 7 publications

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

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

Microstructural evolution and mechanical properties of an ultrahigh-strength Al−Zn−Mg−Cu alloy via powder metallurgy and hot extrusion

Recent advances in hot tearing during casting of aluminium alloys

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