Synergistic effect of gradient Zn content and multiscale particles on the mechanical properties of Al–Zn–Mg–Cu alloys with coupling distribution of coarse–fine grains

Abstract

This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain structure of the alloys, designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe (wt%) alloy with high strength and formability. With the increase of Zn content, forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is easy. This phenomenon induces the formation of cell-like structures with alternate distribution of coarse and fine grains, and the average plasticity–strain ratio (characterizing the formability) of the pre-aged alloy with a high strength is up to 0.708. Results reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the alloys. The developed coupling control process exhibits considerable potential, revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.

Keywords

Al–Zn–Mg–Cu alloy / iron-rich phase / high formability / microstructure / mechanisms

References

[1] Brian C, Grant P, Johnston C. Automotive Engineering: Lightweight, Functional, and Novel Materials, 2008, Boca Raton, CRC Press.

[2] Feng D, Li XD, Zhang XM, Liu SD, Wang JT, Liu Y. The novel heat treatments of aluminium alloy characterized by multistage and non-isothermal routes: A review. J. Cent. South Univ., 2023, 30(9): 2833.

[3] Engler O, Schäfer C, Brinkman HJ, Brecht J, Beiter P, Nijhof K. Flexible rolling of aluminium alloy sheet—Process optimization and control of materials properties. J. Mater. Process. Technol., 2016, 229, 139.

[4] Yuan LL, Guo MX, Yan Y, Feng WJ, Liu ZY, Zhuang LZ. Theoretical design and distribution control of precipitates and solute elements in Al–Zn–Mg–Cu alloys with heterostructure. Trans. Nonferrous Met. Soc. China, 2021, 31(11): 3328.

[5] Schuster PA, Österreicher JA, Kirov G, Sommitsch C, Kessler O, Mukeli E. Characterisation and comparison of process chains for producing automotive structural parts from 7xxx aluminium sheets. Metals, 2019, 9(3): 305.

[6] Shin J, Kim T, Kim D, Kim D, Kim K. Castability and mechanical properties of new 7xxx aluminum alloys for automotive chassis/body applications. J. Alloys Compd., 2017, 698, 577.

[7] Zhang HT, Liu JK. Microstructure characteristics and mechanical property of aluminum alloy/stainless steel lap joints fabricated by MIG welding–brazing process. Mater. Sci. Eng. A, 2011, 528(19–20): 6179.

[8] Xue JY, Li YX, Chen H, Zhu ZT. Wettability, microstructure and properties of 6061 aluminum alloy/304 stainless steel butt joint achieved by laser-metal inert-gas hybrid welding-brazing. Trans. Nonferrous Met. Soc. China, 2018, 28(10): 1938.

[9] Chen SH, Daehn GS, Vivek A, et al. Interfacial microstructures and mechanical property of vaporizing foil actuator welding of aluminum alloy to steel. Mater. Sci. Eng. A, 2016, 659, 12.

[10] Ao M, Ji YC, Yi P, et al. Relationship between elements migration of α-AlFeMnSi phase and micro-galvanic corrosion sensitivity of Al–Zn–Mg alloy. Int. J. Miner. Metall. Mater., 2023, 30(1): 112.

[11] Chen NN, Wang M, Wang HP, Wan ZX, Carlson BE. Microstructural and mechanical evolution of Al/steel interface with Fe₂Al₅ growth in resistance spot welding of aluminum to steel. J. Manuf. Processes, 2018, 34, 424.

[12] Tan P, Sui YD, Jin HN, Zhu S, Jiang YH, Han LN. Effect of Zn content on the microstructure and mechanical properties of as-cast Al–Zn–Mg–Cu alloy with medium Zn content. J. Mater. Res. Technol., 2022, 18, 2620.

[13] Y. Zou, X.D. Wu, S.B. Tang, Y.C. Wang, K. Zhao, and L.F. Cao, The effect of pre-ageing/stretching on the ageing-hardening behavior of Al–Zn–Mg–Cu alloys correlated with Zn/Mg ratio, Mater. Sci. Eng. A, 830(2022), art. No. 142331.

[14] Zheng KL, Politis DJ, Wang LL, Lin JG. A review on forming techniques for manufacturing lightweight complex—shaped aluminium panel components. Int. J. Lightweight Mater. Manuf., 2018, 1(2): 55.

[15] Wang H, Luo YB, Friedman P, Chen MH, Gao L. Warm forming behavior of high strength aluminum alloy AA7075. Trans. Nonferrous Met. Soc. China, 2012, 22(1): 1.

[16] Krajewski PE, Schroth JG. Superplastic Forming of Advanced Metallic Materials, 2011, Cambridge, Woodhead Publishing.

[17] Peng YH, Liu CY, Wei LL, Jiang HJ, Ge ZJ. Quench sensitivity and microstructures of high-Zn-content Al–Zn–Mg–Cu alloys with different Cu contents and Sc addition. Trans. Nonferrous Met. Soc. China, 2021, 31(1): 24.

[18] Wang B, Li JW, Xie ZH, Wang GJ, Yu G. High corrosion and wear resistant electroless Ni–P gradient coatings on aviation aluminum alloy parts. Int. J. Miner. Metall. Mater., 2024, 31(1): 155.

[19] David A, Gopal SK, Lakshmanan P, Chenbagam AS. Corrosion, mechanical and microstructural properties of aluminum 7075—carbon nanotube nanocomposites for robots in corrosive environments. Int. J. Miner. Metall. Mater., 2023, 30(6): 1140.

[20] L.L. Yuan, M.X. Guo, X.G. Dong, and L.Z. Zhuang, Design, evolution, formation and effect mechanism of coupling distributed soft and hard micro-regions in Al–Zn–Mg–Cu–Fe alloys with high formability, Mater. Sci. Eng. A, 855(2022), art. No. 143951.

[21] Yuan LL, Guo MX, Zhang JS, Zhuang LZ. Synergy in hybrid multi-scale particles for the improved formability of Al–Zn–Mg–Cu alloys. J. Mater. Res. Technol., 2021, 10, 1143.

[22] Yuan LL, Guo MX, Yu KC, Zhang JS, Zhuang LZ. Multi-scale iron-rich phases induce fine microstructures in Al–Zn–Mg–Cu–Fe alloys. Philos. Mag., 2021, 101(12): 1417.

[23] She H, Shu D, Chu W, Wang J, Sun BD. Microstructural aspects of second phases in as-cast and homogenized 7055 aluminum alloy with different impurity contents. Metall. Mater. Trans. A, 2013, 44(8): 3504.

[24] Mondal C, Mukhopadhyay AK. On the nature of T(Al₂Mg₃Zn₃) and S(Al₂CuMg) phases present in as-cast and annealed 7055 aluminum alloy. Mater. Sci. Eng. A, 2005, 391(1–2): 367.

[25] Freiburg C, Grushko B. An Al₁₃Fe₄ phase in the Al–Cu–Fe alloy system. J. Alloys Compd., 1994, 210(1–2): 149.

[26] She H, Shu D, Dong AP, Wang J, Sun BD, Lai HC. Relationship of particle stimulated nucleation, recrystallization and mechanical properties responding to Fe and Si contents in hot-extruded 7055 aluminum alloys. J. Mater. Sci. Technol., 2019, 35(11): 2570.

[27] Bennett TA, Petrov RH, Kestens LAI, Zhuang LZ, de Smet P. The effect of particle-stimulated nucleation on texture banding in an aluminium alloy. Scripta Mater., 2010, 63(5): 461.

[28] Troeger LP, Starke EA Jr. Particle-stimulated nucleation of recrystallization for grain-size control and superplasticity in an Al–Mg–Si–Cu alloy. Mater. Sci. Eng. A, 2000, 293(1–2): 19.

[29] L.L. Yuan, M.X. Guo, A.M. Habraken, L. Duchene, and L.Z. Zhuang, Extremely improved formability of Al–Zn–Mg–Cu alloys via micro-domain heterogeneous structure, Mater. Sci. Eng. A, 837(2022), art. No. 142737.

[30] Shabadi R, Suwas S, Kumar S, Roven HJ, Dwarkadasa ES. Texture and formability studies on AA7020 Al alloy sheets. Mater. Sci. Eng. A, 2012, 558, 439.

[31] J.G. Jeon, J.H. Shin, S.E. Shin, and D.H. Bae, Improvement in the anisotropic mechanical properties and formability of Al–Si–Mg–Cu-based alloy sheets, Mater. Sci. Eng. A, 799(2021), art. No. 140199.

[32] Bai YJ, Wang ZX, Jiang B, et al. Anisotropy of mechanical properties of 2297-T87 Al–Li alloy thick plates. Int. J. Miner. Metall. Mater., 2023, 30(11): 2212.

[33] Reyes A, Hopperstad OS, Lademo OG, Langseth M. Modeling of textured aluminum alloys used in a bumper system: Material tests and characterization. Comput. Mater. Sci., 2006, 37(3): 246.