Abstract
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.
Similar content being viewed by others
References
J. Shin, T. Kim, D. Kim, D. Kim, K. Kim, J. Alloys Compd. 2017, vol. 698, pp. 577-590.
Y. Li, X. Gao, Z.R. Zhang, W.L. Xiao, H.X. Li, Q. Du, L. Katgerman, J.S. Zhang, L.Z. Zhuang, Metall. Mater. Trans. A 2017, vol. 48, pp. 4744-4754.
H. Zhao, F. De Geuser, A. Kwiatkowski da Silva, A. Szczepaniak, B. Gault, D. Ponge, D. Raabe, Acta Mater. 2018, vol. 156, pp. 318-329.
D. Gildemeister, Effects of microstructure on hot cracking behavior in Al-Zn-Mg-Cu alloys, TMS Annual Meeting & Exhibition, Springer, Cham, 2018, pp. 1097-1104.
K. Ellingsen, Q. Du, M. M’Hamdi, B.E. Gihleengen, R. Ledal, K.O. Tveito, A. Håkonsen, Experimental study and numerical analysis of cracking during DC casting of large dimension 7075 aluminium billets, TMS Annual Meeting & Exhibition, Springer, Cham, 2018, pp. 895-900.
J. Zuo, L. Hou, J. Shi, H. Cui, L. Zhuang, J. Zhang, J. Alloys Compd. 2017, vol. 708, pp. 1131-1140.
Q.L. Bai, J.C. Liu, H.X. Li, Q. Du, L. Katgerman, J.S. Zhang, L.Z. Zhuang, Mater. Sci. Technol. 2016, vol. 32, pp. 846-854.
D.G. Eskin, Physical metallurgy of direct chill casting of aluminum alloys, CRC Press, Boca Raton, 2008.
S. Benum, D. Mortensen, H. Fjær, H.-G. Øverlie, O. Reiso, On the Mechanism of Surface Cracking in DC Cast 7XXX and 6XXX Extrusion Ingot Alloys, in: J.F. Grandfield, D.G. Eskin (Eds.), Essential Readings in Light Metals: Volume 3 Cast Shop for Aluminum Production, Springer International Publishing, Cham, 2016, pp. 887-894.
Q.L. Bai, J.C. Liu, Y. Li, H.X. Li, Q. Du, J.S. Zhang, L.Z. Zhuang, Hot tearing evaluation and contraction behaviors of four AA7xxx alloys, Mater. Sci. Forum, 2015, vol. 28, pp. 21-26.
Q.L. Bai, Y. Li, H.X. Li, Q. Du, J.S. Zhang, L.Z. Zhuang, Metall. Mater. Trans. A 2016, vol. 47, pp. 4080-4091.
Y. Li, Q. Bai, J. Liu, H. Li, Q. Du, J. Zhang, L. Zhuang, Metall. Mater. Trans. A 2016, vol. 47, pp. 4024-4037.
D. Warrington, D.G. McCartney, Cast Metals 1991, vol. 3, pp. 202-208.
D.G. Eskin, S. Suyitno, L. Katgerman, Prog. Mater Sci. 2004, vol. 49, pp. 629-711.
Aluminum Association (2009) International alloy designations and chemical composition limits for wrought aluminum and wrought aluminum alloys. Aluminum Association, Arlington.
Suyitno, W. Kool, L. Katgerman, Metall. Mater. Trans. A 2005, vol. 36, pp. 1537-1546.
D.G. Eskin, S. Suyitno, J.F. Mooney, L. Katgerman, Metall. Mater. Trans. A 2004, vol. 35, pp. 1325-1335.
Z. Wang, Y. Huang, A. Srinivasan, Z. Liu, F. Beckmann, K.U. Kainer, N. Hort, Mater. Des. 2013, vol. 47, pp. 90-100.
S. Li, K. Sadayappan, D. Apelian, Metall. Mater. Trans. B 2013, vol. 44, pp. 614-623.
G. Cao, I. Haygood, S. Kou, Metall. Mater. Trans. A 2010, vol. 41, pp. 2139-2150.
J.-M. Drezet, B. Mireux, G. Kurtuldu, O. Magdysyuk, M. Drakopoulos, Metall. Mater. Trans. A 2015, vol. 46, pp. 4183-4190.
S. Instone, D. John, J. Grandfield, Int. J. Cast Met. Res. 2000, vol. 12, pp. 441-456.
M. Pekguleryuz, X. Li, C. Aliravci, Metall. Mater. Trans. A 2009, vol. 40, pp. 1436-1456.
A. Stangeland, A. Mo, M. M’Hamdi, D. Viano, C. Davidson, Metall. Mater. Trans. A 2006, vol. 37, pp. 705-714.
D. Viano, D. StJohn, J. Grandfield, C. Cáceres, Hot tearing in aluminium-copper alloys, Springer, Cham2016.
J. Mitchell, S. Cockcroft, D. Viano, C. Davidson, D. StJohn, Metall. Mater. Trans. A 2007, vol. 38, pp. 2503-2512.
L. Sweet, J. Taylor, M. Easton, M. Couper, N. Parson, Chemical additions to reduce hot tearing in the cast house Light Metals, Springer, Cham, 2012, pp. 1133-1138.
M.A. Easton, H. Wang, J. Grandfield, C.J. Davidson, D.H. StJohn, L.D. Sweet, M.J. Couper, Metall. Mater. Trans. A 2012, vol. 43, pp. 3227-3238.
L. Sweet, M.A. Easton, J.A. Taylor, J.F. Grandfield, C.J. Davidson, L. Lu, M.J. Couper, D.H. StJohn, Metall. Mater. Trans. A 2013, vol. 44, pp. 5396-5407.
M. M’Hamdi, A. Mo, H.G. Fjær, Metall. Mater. Trans. A 2006, vol. 37, pp. 3069-3083.
Suyitno, W. Kool, L. Katgerman, Metall. Mater. Trans. A 2009, vol. 40, pp. 2388-2400.
M. Rappaz, J.-M. Drezet, M. Gremaud, Metall. Mater. Trans. A 1999, vol. 30, pp. 449-455.
L. Zhang, D.G. Eskin, M. Lalpoor, L. Katgerman, Mater. Sci. Eng. A, 2010, vol. 527, pp. 3264-3270.
A. Dinsdale, P. Quested, J Mater Sci 2004, vol. 39, pp. 7221-7228.
A.L. Greer, A.M. Bunn, A. Tronche, P.V. Evans, D.J. Bristow, Acta Mater. 2000, vol. 48, pp. 2823-2835.
M. Easton, H. Wang, J. Grandfield, D. John, E. Sweet, Mater. Forum 2004, vol. 28, pp. 224-229.
S. Vernède, J.A. Dantzig, M. Rappaz, Acta Mater. 2009, vol. 57, pp. 1554-1569.
M. Sistaninia, S. Terzi, A.B. Phillion, J.M. Drezet, M. Rappaz, Acta Mater. 2013, vol. 61, pp. 3831-3841.
S. Geng, P. Jiang, X. Shao, G. Mi, H. Wu, Y. Ai, C. Wang, C. Han, R. Chen, W. Liu, Y. Zhang, Acta Mater. 2018, vol. 160, pp. 85-96.
J.F. Grandfield, C.J. Davidson, J.A. Taylor (2000) Contin Cast, 24, pp. 205-210.
Acknowledgments
This study was supported by the Major State Research and Development Program of China (Grant No. 2016YFB0300801); the National Natural Science Foundation of China (Grant No. 51671017); the Beijing Laboratory of Metallic Materials and Processing for Modern Transportation; and the Fundamental Research Funds for the Central Universities (Grant No. FRF-GF-17-B3). The authors would like to thank Dr. Q. Du from SINTEF for a valuable discussion.
Conflict of interest
The authors declare that they have no competing interests.
Author information
Authors and Affiliations
Corresponding authors
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Manuscript submitted February 5, 2019.
Rights and permissions
About this article
Cite this article
Li, Y., Zhang, Z.R., Zhao, Z.Y. et al. Effect of Main Elements (Zn, Mg, and Cu) on Hot Tearing Susceptibility During Direct-Chill Casting of 7xxx Aluminum Alloys. Metall Mater Trans A 50, 3603–3616 (2019). https://doi.org/10.1007/s11661-019-05268-z
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11661-019-05268-z