Effect of Heat Treatment on the Microstructural Characteristics and Mechanical Properties of Al-Zn-Mg-Cu-Sc Alloy Prepared via Wire-Arc Directed Energy Deposition Process

doi:10.11900/0412.1961.2025.00048

Acta Metall Sin

2025, Vol. 61

Issue (10): 1542-1554 DOI: 10.11900/0412.1961.2025.00048

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Effect of Heat Treatment on the Microstructural Characteristics and Mechanical Properties of Al-Zn-Mg-Cu-Sc Alloy Prepared via Wire-Arc Directed Energy Deposition Process

QIN Fengming, LI Yafei, LI Yajie(

), ZHAO Xiaodong, LIANG Shangshang, CHEN Jinqiu

School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China

Cite this article:

QIN Fengming, LI Yafei, LI Yajie, ZHAO Xiaodong, LIANG Shangshang, CHEN Jinqiu. Effect of Heat Treatment on the Microstructural Characteristics and Mechanical Properties of Al-Zn-Mg-Cu-Sc Alloy Prepared via Wire-Arc Directed Energy Deposition Process. Acta Metall Sin, 2025, 61(10): 1542-1554.

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Abstract

Wire-arc directed energy deposition (DED) shows considerable potential for fabricating structural components from Al-Zn-Mg-Cu-Sc alloys. However, its layer-by-layer deposition nature leads to continuous grain boundary second-phase networks, grain coarsening, elemental microsegregation, and residual stress accumulation during solidification of 7075-Sc aluminum alloys, significantly compromising their mechanical properties and industrial viability. As a precipitation-strengthened alloy, 7075 can be optimized through heat treatment to control the morphology and distribution of secondary phases, thereby improving mechanical performance. Nevertheless, the inhomogeneous as-deposited microstructure proves difficult to fully homogenize using conventional heat treatment, necessitating precise temperature control and tailored aging schedules for effective thermal processing. In this study, crack-free, thick-walled Al-Zn-Mg-Cu-Sc alloy components were fabricated using custom 7075-Sc welding wire and the cold metal transfer process. Microstructural analysis revealed that the as-deposited alloy consists of fine equiaxed grains with an average diameter of approximately 14 μm and a continuous grain boundary second-phase distribution. Solution treatment at 470 ^oC results in a markedly reduced dissolution rate of the secondary phases over time, with a 4 h duration identified as optimal. Under this condition, 70.2% of the secondary phases are dissolved; the remaining phases are predominantly Al₇Cu₂Fe and Al₂Mg₃Zn₃. Subsequent artificial aging at 120 ^oC showed that an aging time of 18 h yields optimal mechanical properties. Following the combined solution and aging treatments, the alloy exhibited a yield strength of 475.2 MPa, tensile strength of 542.1 MPa, and elongation of 5.2%. These values represent increases of 52.8%, 36.5%, and 36.8%, respectively, compared to the as-deposited alloy.

Key words: Al-Zn-Mg-Cu-Sc alloy wire-arc directed energy deposition (DED) heat treatment microstructure mechanical property

Received: 24 February 2025

ZTFLH:

TG456.9

Fund: Central Government Guides Local Funds for Science and Technology Development(YDZJSX20231A045);Central Government Guides Local Funds for Science and Technology Development(YDZJSX2024D053);Start-up Fund for Scientific Research of Taiyuan University of Science and Technology(20-232074);Start-up Fund for Scientific Research of Taiyuan University of Science and Technology(20212011);Start-up Fund for Scientific Research of Taiyuan University of Science and Technology(20222063);Natural Science Foundation of Shanxi Province(202303021212216)

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	Articles by authors
	QIN Fengming
	LI Yafei
	LI Yajie
	ZHAO Xiaodong
	LIANG Shangshang
	CHEN Jinqiu

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https://www.ams.org.cn/EN/10.11900/0412.1961.2025.00048 OR https://www.ams.org.cn/EN/Y2025/V61/I10/1542

Fig.1 Schematic of the wire-arc directed energy deposition (DED) process (a), photos of the deposited sample (b), and schematic of the experimental sampling location (unit: mm) (c) (A₁—amplitude, A₂—length, l₀—gauge length, l_c—parallel length)

Table 1 Chemical compositions of the materials

Fig.2 OM (a) and SEM (b) images of the as-deposited Zn-Mg-Cu-Sc sample, and SEM images of solution-treated samples at 470 ^oC for 2 h (c), 4 h (d), and 6 h (e) (Insets in Figs.2c-e are locally enlarged images of the boxed areas; the arrows point to the pores)

Fig.3 EBSD inverse pole figures (a1-d1), pole figures (a2-d2), and grain size statistics (a3-d3) of the wire-arc DED alloys under the as-deposited state (a1-a3) and as-aged at 470 ^oC, 4 h + 120 ^oC, 12 h (b1-b3), 470 ^oC, 4 h + 120 ^oC, 18 h (c1-c3), and 470 ^oC, 4 h + 120 ^oC, 24 h (d1-d3)

Fig.4 Grain boundary maps and misorientation angle statistical results (insets) of the wire-arc DED alloys under the as-deposited state (a) and as-aged at 470 ^oC, 4 h + 120 ^oC, 12 h (b), 470 ^oC, 4 h + 120 ^oC, 18 h (c), and 470 ^oC, 4 h + 120 ^oC, 24 h (d) (Red and blue grain boundaries represent low angle grain boundaries (LAGBs) and high angle grain boundaries (HAGBs), respectively)

Fig.5 SEM images (a1-d1) and elemental EDS analyses (a2-d2) of the wire-arc DED alloy under the as-deposited state (a1, a2) and as-aged at 470 ^oC, 4 h + 120 ^oC, 12 h (b1, b2), 470 ^oC, 4 h + 120 ^oC, 18 h (c1, c2), and 470 ^oC, 4 h + 120 ^oC, 24 h (d1, d2)

Fig.6 Micro-area XRD spectra of as-deposited and heat-treated samples with different time

Fig.7 Hardnesses of as-deposited and heat-treated samples with different time

Fig.8 Engineering stress-strain curves (a) and tensile properties (b) of as-deposited and heat-treated samples with different time

Fig.9 Tensile fracture morphologies with different magnifications of the wire-arc DED alloys samples under the as-deposited state (a1-a3) and as-aged at 470 ^oC, 4 h + 120 ^oC, 12 h (b1-b3), 470 ^oC, 4 h + 120 ^oC,18 h (c1-c3), and 470 ^oC, 4 h + 120 ^oC, 24 h (d1-d3)

Fig.10 TEM images (a, b, d, e) and high resolution TEM images and corresponding fast Fourier transform (FFT) (c, f) of as-deposited (a-c) and heat-treated (470 ^oC, 4 h + 120 ^oC,18 h) (d-f) samples (PFZ—precipitation free zone, d—spacing)

Fig.11 Contributions of strengthening mechanisms in as-deposited and heat-treated alloys

[1]	Williams J C, Starke E A. Progress in structural materials for aerospace systems [J]. Acta Mater., 2003, 51: 5775
[2]	Panigrahi S K, Jayaganthan R. Development of ultrafine grained high strength age hardenable Al 7075 alloy by cryorolling [J]. Mater. Des., 2011, 32: 3150
[3]	Dursun T, Soutis C. Recent developments in advanced aircraft aluminium alloys [J]. Mater. Des. (1980-2015), 2014, 56: 862
[4]	DebRoy T, Wei H L, Zuback J S, et al. Additive manufacturing of metallic components—Process, structure and properties [J]. Prog. Mater. Sci., 2018, 92: 112
[5]	Zhang J L, Song B, Wei Q S, et al. A review of selective laser melting of aluminum alloys: Processing, microstructure, property and developing trends [J]. J. Mater. Sci. Technol., 2019, 35: 270 doi: 10.1016/j.jmst.2018.09.004
[6]	Oko O E, Mbakaan C, Barki E. Experimental investigation of the effect of processing parameters on densification, microstructure and hardness of selective laser melted 7075 aluminium alloy [J]. Mater. Res. Express, 2020, 7: 036512
[7]	Bartsch H, Kühne R, Citarelli S, et al. Fatigue analysis of wire arc additive manufactured (3D printed) components with unmilled surface [J]. Structures, 2021, 31: 576
[8]	Wu B T, Pan Z X, Ding D H, et al. A review of the wire arc additive manufacturing of metals: Properties, defects and quality improvement [J]. J. Manuf. Processes, 2018, 35: 127
[9]	Zhao Y N, Guo Q Y, Liu C X, et al. Effects of subsequent heat treatment on microstructure and high-temperature mechanical properties of laser 3D printed GH4099 alloy [J]. Acta Metall. Sin., 2025, 61: 165
	赵亚楠, 郭乾应, 刘晨曦等. 后续热处理对激光3D打印GH4099合金微观组织和高温力学性能的影响 [J] 金属学报, 2025, 61: 165 doi: 10.11900/0412.1961.2024.00208
[10]	Xia X C, Zhang E K, Ding J, et al. Research progress on laser cladding of refractory high-entropy alloy coatings [J]. Acta Metall. Sin., 2025, 61: 59 doi: 10.11900/0412.1961.2024.00146
	夏兴川, 张恩宽, 丁俭等. 激光熔覆难熔高熵合金涂层研究进展 [J] 金属学报, 2025, 61: 59 doi: 10.11900/0412.1961.2024.00146
[11]	Yu Z L, Yuan T, Xu M, et al. Microstructure and mechanical properties of Al-Zn-Mg-Cu alloy fabricated by wire + arc additive manufacturing [J]. J. Manuf. Processes, 2021, 62: 430
[12]	Wang L W, Wu T, Wang D L, et al. A novel heterogeneous multi-wire indirect arc directed energy deposition for in-situ synthesis Al-Zn-Mg-Cu alloy: Process, microstructure and mechanical properties [J]. Addit. Manuf., 2023, 72: 103639
[13]	Cai X Y, Xia Y H, Dong B L, et al. Effects of deposition paramaters on the microstructure evolution of wire arc additive manufactured Al-Zn-Mg-Cu alloy [J]. J. Mater. Res. Technol., 2023, 26: 1572
[14]	Ren L L, Gu H M, Wang W, et al. Effect of Sc content on the microstructure and properties of Al-Mg-Sc alloys deposited by wire arc additive manufacturing [J]. Met. Mater. Int., 2021, 27: 68
[15]	Xia Y H, Cai X Y, Dong B L, et al. Wire arc additive manufacturing of Al-Mg-Sc alloy: An analysis of the effect of Sc on microstructure and mechanical properties [J]. Mater. Charact., 2023, 203: 113116
[16]	Dong B L, Xia Y H, Cai X Y, et al. Addition of Sc in wire-based directed energy deposition of Al-Mg-Zn-Cu alloy: Microalloying to refine grains and improve mechanical properties [J]. Addit. Manuf., 2023, 67: 103494
[17]	Klein T, Schnall M, Gomes B, et al. Wire-arc additive manufacturing of a novel high-performance Al-Zn-Mg-Cu alloy: Processing, characterization and feasibility demonstration [J]. Addit. Manuf., 2021, 37: 101663
[18]	Miao J L, Chen J Q, Ting X, et al. Effect of solution treatment on porosity, tensile properties and fatigue resistance of Al-Cu alloy fabricated by wire arc additive manufacturing [J]. J. Mater. Res. Technol., 2024, 28: 1864
[19]	Hao S, Guo X P, Cui J Y, et al. Study on the solid solution temperature of achieving ultra-high strength in wire-arc additive manufactured Al-Zn-Mg-Cu aluminum alloy [J]. Mater. Charact., 2023, 201: 112975
[20]	Fu R, Lu W J, Guo Y L, et al. Achieving high strength-ductility of Al-Zn-Mg-Cu alloys via hot-wire arc additive manufacturing enabled by strengthening precipitates [J]. Addit. Manuf., 2022, 58: 103042
[21]	Zou X L, Yan H, Chen X H. Evolution of second phases and mechanical properties of 7075 Al alloy processed by solution heat treatment [J]. Trans. Nonferrous Met. Soc. China, 2017, 27: 2146
[22]	Dai Y X, Yan L M, Hao J P. Microstructure and intermetallic phase evolution during the homogenization of an Al-Zn-Mg-Cu-Zr-Nd aluminum alloy [J]. Adv. Eng. Mater., 2023, 25: 2201288
[23]	Cheng S X, Liu F C, Xu Y, et al. Effects of arc oscillation on microstructure and mechanical properties of AZ31 magnesium alloy prepared by CMT wire-arc directed energy deposition [J]. Mater. Sci. Eng., 2023, A864: 144539
[24]	Bi J, Lei Z L, Chen Y B, et al. Microstructure and mechanical properties of a novel Sc and Zr modified 7075 aluminum alloy prepared by selective laser melting [J]. Mater. Sci. Eng., 2019, A768: 138478
[25]	Yu J, Kim J Y. Effects of residual S on Kirkendall void formation at Cu/Sn-3.5Ag solder joints [J]. Acta Mater., 2008, 56: 5514
[26]	Toda H, Hidaka T, Kobayashi M, et al. Growth behavior of hydrogen micropores in aluminum alloys during high-temperature exposure [J]. Acta Mater., 2009, 57: 2277
[27]	Lin B, Wang K, Liu F, et al. An intrinsic correlation between driving force and energy barrier upon grain boundary migration [J]. J. Mater. Sci. Technol., 2018, 34: 1359 doi: 10.1016/j.jmst.2017.11.002
[28]	Feng J, Ye B, Zuo L J, et al. Effects of Zr, Ti and Sc additions on the microstructure and mechanical properties of Al-0.4Cu-0.14Si-0.05Mg-0.2Fe alloys [J]. J. Mater. Sci. Technol., 2018, 34: 2316 doi: 10.1016/j.jmst.2018.05.011
[29]	Marquis E A, Seidman D N. Nanoscale structural evolution of Al₃Sc precipitates in Al(Sc) alloys [J]. Acta Mater., 2001, 49: 1909
[30]	Chung T F, Yang Y L, Huang B M, et al. Transmission electron microscopy investigation of separated nucleation and in-situ nucleation in AA7050 aluminium alloy [J]. Acta Mater., 2018, 149: 377
[31]	Dong B L, Cai X Y, Xia Y H, et al. Step solution treatment of a wire-arc directed energy deposited Al-Zn-Mg-Cu alloy: Defects suppression and mechanical property improvement [J]. Virtual Phys. Prototyp., 2024, 19: e2382170
[32]	Yang W H, Zhang Y L, Yang H F, et al. Effect of non-isothermal retrogression and re-aging treatment on microstructure evolution and mechanical properties of Al-Zn-Mg-Cu alloy [J]. J. Mater. Res. Technol., 2024, 31: 1728
[33]	Liu Y, Jiang D M, Li W J. The effect of multistage ageing on microstructure and mechanical properties of 7050 alloy [J]. J. Alloys Compd., 2016, 671: 408
[34]	Wang Z, Wang S G, Zhang C C, et al. Effect of post-weld heat treatment on microstructure and mechanical properties of 7055 aluminum alloy electron beam welded joint [J]. Mater. Res. Express, 2020, 7: 066528
[35]	Scheiber D, Jechtl T, Svoboda J, et al. On solute depletion zones along grain boundaries during segregation [J]. Acta Mater., 2020, 182: 100 doi: 10.1016/j.actamat.2019.10.040
[36]	Ogura T, Hirosawa S, Cerezo A, et al. Atom probe tomography of nanoscale microstructures within precipitate free zones in Al-Zn-Mg(-Ag) alloys [J]. Acta Mater., 2010, 58: 5714
[37]	Zhao H, De Geuser F, Kwiatkowski da Silva A, et al. Segregation assisted grain boundary precipitation in a model Al-Zn-Mg-Cu alloy [J]. Acta Mater., 2018, 156: 318
[38]	Krug M E, Mao Z G, Seidman D N, et al. Comparison between dislocation dynamics model predictions and experiments in precipitation-strengthened Al-Li-Sc alloys [J]. Acta Mater., 2014, 79: 382
[39]	Li Y J, Ma C R, Qin F M, et al. The microstructure and mechanical properties of 316L austenitic stainless steel prepared by forge and laser melting deposition [J]. Mater. Sci. Eng., 2023, A870: 144820
[40]	Liu D H, Wu D J, Ma G Y, et al. Effect of post-deposition heat treatment on laser-TIG hybrid additive manufactured Al-Cu alloy [J]. Virtual Phys. Prototyp., 2020, 15: 445
[41]	Ma K K, Wen H M, Hu T, et al. Mechanical behavior and strengthening mechanisms in ultrafine grain precipitation-strengthened aluminum alloy [J]. Acta Mater., 2014, 62: 141
[42]	Booth-Morrison C, Dunand D C, Seidman D N. Coarsening resistance at 400 ^oC of precipitation-strengthened Al-Zr-Sc-Er alloys [J]. Acta Mater., 2011, 59: 7029

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