Effect of Cu content on mechanical and intergranular corrosion properties of Al-Cu-Mg-Ag alloy

Abstract

The differences in the microstructure, mechanical properties, and intergranular corrosion performance of three Al-Cu-Mg-Ag alloys with varying Cu content were analyzed. The results show that Cu content primarily affects the precipitation of intragranular Ω and S′ phases, as well as the type and distribution of grain boundary precipitates (GBPs). As the amount of Cu increases, the diameter and volume fraction of the Ω phase increase, while the proportion of the S′ phase first increases and then decreases. The alloy with high Cu content exhibits higher strength, mainly due to a larger contribution from precipitate strengthening (mainly the Ω phase) and strengthening provided by additional Cu atoms. However, the lower number density of the Ω phase results in poor fatigue resistance. The GBPs transition from the intermittently distributed S phase to the continuously distributed S and θ phases, which is the main reason for the decrease of intergranular corrosion resistance in high Cu alloys and also has some impact on the fatigue resistance of the alloy. Electrochemical characteristics also show that high Cu alloys have higher free corrosion current density and corrosion rate, lower polarization resistance, and smaller charge transfer resistance of the double layer and inductance values.

Keywords

Al-Cu-Mg-Ag alloy / Cu content / microstructure evolution / Ω phase

References

[1] Deng P, Mo W-f, Ouyang Z-q, et al.. Mechanical properties and corrosion behaviors of (Sc, Zr) modified Al-Cu-Mg alloy [J]. Materials Characterization, 2023, 196: 112619

[2] Luo C, Zhou X, Thompson G E, et al.. Observations of intergranular corrosion in AA2024-T351: The influence of grain stored energy [J]. Corrosion Science, 2012, 61: 35-44

[3] Bai S, Yi X-l, Liu Z-yi. On the role of Ag additions on the initial solute hardening and competitive precipitation of Al-Cu-Mg alloys [J]. Journal of Alloys and Compounds, 2023, 945: 169339

[4] Deng P, Mo W-f, Ouyang Z-q, et al.. Microstructural evolution and corrosion mechanism of micro-alloyed 2024 (Zr, Sc, Ag) aluminum alloys [J]. Corrosion Science, 2023, 224: 111476

[5] Vural M, Caro J. Experimental analysis and constitutive modeling for the newly developed 2139-T8 alloy [J]. Materials Science and Engineering A, 2009, 520(1): 56-65 2

[6] Ouyang Z-q, Deng P, Mo W-f, et al.. Effect of final rolling temperature on microstructure and intergranular corrosion resistance of an Al-Cu-Mg-Ag alloy [J]. Journal of Materials Research and Technology, 2024, 30: 4109-4122

[7] Reich L, Murayama M, Hono K. Evolution of Ω phase in an Al-Cu-Mg-Ag alloy: A three-dimensional atom probe study [J]. Acta Materialia, 1998, 46(17): 6053-6062

[8] Knipling K E, Karnesky R A, Lee C P, et al.. Precipitation evolution in Al-0.1Sc, Al-0.1Zr and Al-0.1Sc-0.1Zr (at.%) alloys during isochronal aging [J]. Acta Materialia, 2010, 58(15): 5184-5195

[9] Knowles K M, Stobbs W M. The structure of {111} age-hardening precipitates in Al-Cu-Mg-Ag alloys [J]. Acta Crystallographica B-Structural Science, 1988, 44(3): 207-227

[10] Muddle B C, Polmear I J. The precipitate Ω phase in Al-Cu-Mg-Ag alloys [J]. Acta Metallurgica, 1989, 37(3): 777-789

[11] Yang S L, Wilson N, Nie J F. Revisit of the structure of Ω precipitate in Al-Cu-Mg-Ag alloys [J]. Scripta Materialia, 2021, 205: 114204

[12] Yang S L, Zhao X J, Chen H W, et al.. Atomic structure and evolution of a precursor phase of Ω precipitate in an Al-Cu-Mg-Ag alloy [J]. Acta Materialia, 2022, 225: 117538

[13] Deng S-x, Li J-f, Ning H, et al.. Effect of Zr addition on the microstructure evolution and mechanical properties of extruded Al-Cu-Li-Mn alloys [J]. Materials Characterization, 2023, 202: 113011

[14] Guo S, Liu Z-y, Bai S, et al.. Effect of rolling temperature on mechanical properties and corrosion resistance of Al-Cu-Mg-Ag alloy [J]. Journal of Alloys and Compounds, 2022, 897: 163168

[15] Guo J-c, Jin M-l, Su R-m, et al.. Microstructural morphology and mechanical properties of deep cryogenic treatment modified Al-Cu-Mg-Ag alloy [J]. Materials Today Communications, 2024, 38: 107670

[16] Tang C-l, Luo B-h, Bai Z-h, et al.. Effect of non-isothermal ageing on microstructure and mechanical properties of an Al-Cu-Mg-Ag alloy [J]. Materials Science and Engineering A, 2022, 830: 142315

[17] Zhang J-b, Zhang Y-a, Zhu B-h, et al.. Characterization of microstructure and mechanical properties of Al-Cu-Mg-Ag- (Mn/Zr) alloy with high Cu: Mg [J]. Materials & Design, 2013, 49: 311-317

[18] Bai S, Yi X-l, Liu G-h, et al.. Effect of Sc addition on the microstructures and age-hardening behavior of an Al-Cu-Mg-Ag alloy [J]. Materials Science and Engineering A, 2019, 756: 258-267

[19] Bai S, Huang T-t, Xu H, et al.. Effects of small Er addition on the microstructural evolution and strength properties of an Al-Cu-Mg-Ag alloy aged at 200 °C [J]. Materials Science and Engineering A, 2019, 766: 138351

[20] Xiao D-h, Huang B-yun. Effect of Yb addition on precipitation and microstructure of Al-Cu-Mg-Ag alloys [J]. Transactions of Nonferrous Metals Society of China, 2007, 17(6): 1181-1185

[21] Song M, Chen K-h, Huang L-ping. Effects of Ce and Ti on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy [J]. Rare Metals, 2007, 26(1): 28-32

[22] Mei Z-q, Liu Z-y, Bai S, et al.. Effects of yttrium additions on microstructures and mechanical properties of cast Al-Cu-Mg-Ag alloys [J]. Journal of Alloys and Compounds, 2021, 870: 159435

[23] Xu H, Dong Y, Bai S, et al.. Effect of small Sn addition on the initial strengthening and microstructural evolution of an Al-Cu-Mg-Ag alloy [J]. Journal of Alloys and Compounds, 2023, 943: 169167

[24] Ling K, Chen J-w, Ran H-w, et al.. Effect of V additions on the microstructure and mechanical properties of Al-Cu-Mg-Ag alloy [J]. Materials Today Communications, 2022, 33: 104197

[25] So H, Won S J, Park J, et al.. Mechanical properties and microstructural evolution in Al-Cu-Mg-Ag alloy with a Cu_xMg_x/10 content [J]. Materials Science and Engineering A, 2021, 824: 141573

[26] Xiao D H, Wang J N, Ding D Y, et al.. Effect of Cu content on the mechanical properties of an Al-Cu-Mg-Ag alloy [J]. Journal of Alloys and Compounds, 2002, 343(1): 77-81 2

[27] Chen J-w, Ling K, Deng P, et al.. Effect of Mg content on microstructure, mechanical properties and intergranular corrosion properties of Al-Cu-Mg-Ag alloys [J]. Materials Today Communications, 2023, 34: 105363

[28] Liu X-y, Wang Z-p, Fu B-g, et al.. Effects of Mg content on the mechanical properties and corrosion resistance of Al-Cu-Mg-Ag alloy [J]. Journal of Alloys and Compounds, 2016, 685: 209-215

[29] Bai S, Zhou X-w, Liu Z-y, et al.. Atom probe tomography study of Mg-dependent precipitation of Ω phase in initial aged Al-Cu-Mg-Ag alloys [J]. Materials Science and Engineering A, 2015, 637: 183-188

[30] Bai S, Zhou X-w, Liu Z-y, et al.. Effects of Ag variations on the microstructures and mechanical properties of Al-Cu-Mg alloys at elevated temperatures [J]. Materials Science and Engineering A, 2014, 611: 69-76

[31] Chen M C, Chung T F, Tai C L, et al.. Quantitative evaluation of the effect of Ag-addition on the concurrently-existing precipitation kinetics in the aged Al-Cu-Mg(-Ag) alloys [J]. Materials & Design, 2023, 227: 111766

[32] Walker K F, Grice A, Newman J C, et al.. Simulation of fatigue crack growth in aluminium alloy 7075-T7351 under spike overload and aircraft spectrum loading [J]. International Journal of Fatigue, 2025, 190: 108660

[33] Zeng G-j, Li H-r, Lin B, et al.. Influence of grain structure and precipitates on fatigue crack propagation behaviors of Al-xCu-1.2Li-X alloys [J]. Journal of Alloys and Compounds, 2024, 1006: 176309

[34] Liu Q-l, Li X-w, Xiao W, et al.. Disclosing the formation mechanisms of Ag-containing Laves phases at the atomic scale in an Al-Cu-Mg-Ag alloy [J]. Journal of Materials Science & Technology, 2024, 184: 111-121

[35] Gazizov M R, Boev A O, Marioara C D, et al.. Precipitate/matrix incompatibilities related to the {111}Al Ω plates in an Al-Cu-Mg-Ag alloy [J]. Materials Characterization, 2021, 182: 111586

[36] Schijve J. Four lectures on fatigue crack growth [J]. Engineering Fracture Mechanics, 1979, 11(1): 167-168

[37] Lu D-d, Lin B, Liu T-l, et al.. Effect of grain structure on fatigue crack propagation behavior of Al-Cu-Li alloys [J]. Journal of Materials Science & Technology, 2023, 148: 75-89

[38] Lu D-d, Ning H, Deng S-x, et al.. Influence of microstructure on fatigue crack propagation behaviors of Al-xCu-1.5Li-X alloys [J]. International Journal of Fatigue, 2023, 167: 107363

[39] Porter D, Easterling KPhase transformations in metals and alloys (Revised Reprint) [M], 2009Boca RatonCRC Press

[40] Zamani M, Toschi S, Morri A, et al.. Optimisation of heat treatment of Al-Cu- (Mg-Ag) cast alloys [J]. Journal of Thermal Analysis and Calorimetry, 2020, 139(6): 3427-3440

[41] Nie J F, Muddle B C. Strengthening of an Al-Cu-Sn alloy by deformation-resistant precipitate plates [J]. Acta Materialia, 2008, 56(14): 3490-3501

[42] Polmear I, Stjohn D, Nie J F, et al.2-Physical metallurgy of aluminium alloys [M], 2017BostonButterworth-Heinemann31-107

[43] Xie Y-k, Deng Y-l, Wang Y, et al.. Effect of asymmetric rolling and subsequent ageing on the microstructure, texture and mechanical properties of the Al-Cu-Li alloy [J]. Journal of Alloys and Compounds, 2020, 836: 155445

[44] Kurmanaeva L, Topping T D, Wen H-m, et al.. Strengthening mechanisms and deformation behavior of cryomilled Al-Cu-Mg-Ag alloy [J]. Journal of Alloys and Compounds, 2015, 632: 591-603

[45] Fan J-c, Yang B-w, Wang Y, et al.. Enhancing the tensile strength and heat resistance induced by high-density Ω phases in an Al-Cu-Mg-Ag alloy [J]. Journal of Materials Research and Technology, 2022, 18: 3347-3357

[46] Myhr O R, Grong Ø, Andersen S J. Modelling of the age hardening behaviour of Al-Mg-Si alloys [J]. Acta Materialia, 2001, 49(1): 65-75

[47] Zhong Z Y, Brokmeier H G, Gan W M, et al.. Dislocation density evolution of AA 7020-T6 investigated by in-situ synchrotron diffraction under tensile load [J]. Materials Characterization, 2015, 108: 124-131

[48] Kim Y, Gu G H, Kim H S. Fundamental analysis of deformation behavior in core-shell heterostructured materials [J]. Computational Materials Science, 2022, 215: 111818

[49] Bowen J R, Prangnell P B, Juul Jensen D, et al.. Microstructural parameters and flow stress in Al-0.13% Mg deformed by ECAE processing [J]. Materials Science and Engineering A, 2004, 387: 235-239

[50] Hansen N, Huang X. Microstructure and flow stress of polycrystals and single crystals [J]. Acta Materialia, 1998, 46(5): 1827-1836

[51] Liu Q, Huang X, Lloyd D J, et al.. Microstructure and strength of commercial purity aluminium (AA 1200) cold-rolled to large strains [J]. Acta Materialia, 2002, 50(15): 3789-3802

[52] Gazizov M R, Boev A O, Marioara C D, et al.. Edge interfaces of the Ω plates in a peak-aged Al-Cu-Mg-Ag alloy [J]. Materials Characterization, 2022, 185: 111747

[53] Tang C-l, Mo W-f, Wang L, et al.. Atomic insight into the shearing behavior of precipitates in an Al-Cu-Mg-Ag alloy [J]. Acta Materialia, 2024, 268: 119737

[54] Nie J F, Muddle B C, Polmear I J. The effect of precipitate shape and orientation on dispersion strengthening in high strength aluminium alloys [J]. Materials Science Forum, 1996, 217–222: 1257-1262

[55] Nie J F, Muddle B C. Microstructural design of high-trength aluminum alloys [J]. Journal of Phase Equilibria, 1998, 19(6): 543-551

[56] Masoumi M, Ariza E A, Sinatora A, et al.. Role of crystallographic orientation and grain boundaries in fatigue crack propagation in used pearlitic rail steel [J]. Materials Science and Engineering A, 2018, 722: 147-155

[57] Gazizov M, Teleshov V, Zakharov V, et al.. Solidification behaviour and the effects of homogenisation on the structure of an Al-Cu-Mg-Ag-Sc alloy [J]. Journal of Alloys and Compounds, 2011, 509(39): 9497-9507

[58] Liu Y, Zhang Y, Xiao N-m, et al.. Investigating interfacial segregation of Ω/Al in Al-Cu alloys: A comprehensive study using density functional theory and machine learning [J]. Acta Materialia, 2024, 279: 120294

[59] Honma T, Yanagita S, Hono K, et al.. Coincidence Doppler broadening and 3DAP study of the pre-precipitation stage of an Al-Li-Cu-Mg-Ag alloy [J]. Acta Materialia, 2004, 52(7): 1997-2003

[60] Fonda R W, Cassada W A, Shiflet G J. Accomodation of the misfit strain surrounding{III} precipitates (Ω) in Al-Cu-Mg- (Ag) [J]. Acta Metallurgica et Materialia, 1992, 40(10): 2539-2546

[61] Li H, Xu W, Wang Z-x, et al.. Effects of re-ageing treatment on microstructure and tensile properties of solution treated and cold-rolled Al-Cu-Mg alloys [J]. Materials Science and Engineering A, 2016, 650: 254-263

[62] Dumont D, Deschamps A, Brechet Y. On the relationship between microstructure, strength and toughness in AA7050 aluminum alloy [J]. Materials Science and Engineering A, 2003, 356(1): 326-336 2

[63] Birbilis N, Buchheit R G. Electrochemical characteristics of intermetallic phases in aluminum alloys [J]. Journal of the Electrochemical Society, 2005, 152(4): B140

[64] Cao F H, Zhang Z, Su J X, et al.. Electrochemical impedance spectroscopy analysis on aluminum alloys in EXCO solution [J]. Materials and Corrosion, 2005, 56(5): 318-324

[65] Deng P, Mo W-f, Ouyang Z-q, et al.. Effect of Zr content on corrosion behavior and chemically-milled surface roughness of Al-Cu-Mg alloy [J]. Journal of Alloys and Compounds, 2023, 965: 171364

[66] Bergant Z, Trdan U, Grum J. Effect of high-temperature furnace treatment on the microstructure and corrosion behavior of NiCrBSi flame-sprayed coatings [J]. Corrosion Science, 2014, 88: 372-386

[67] Yin Y, Luo B-h, Jing H-b, et al.. Influences of quench cooling rate on microstructure and corrosion resistance of Al-Cu-Mg alloy based on the end-quenching test [J]. Metallurgical and Materials Transactions B, 2018, 49(5): 2241-2251

[68] Chang F-c, Song Y-w, Dong K-h, et al.. Study on the synergistic effect of second phases and product films to significantly improve the corrosion resistance of Mg-Gd-Y-Nd alloy [J]. Corrosion Science, 2024, 237: 112304

[69] Peng Y-c, Huang B, Zhong Y-f, et al.. Electrochemical corrosion behavior of 6061 Al alloy under high rotating speed submerged friction stir processing [J]. Corrosion Science, 2023, 215: 111029

[70] Xiao Y, Lin B, Tang J-l, et al.. Effect of elastic tensile stress on the pitting corrosion mechanism and passive film of 2205 duplex stainless steel [J]. Electrochimica Acta, 2024, 477: 143765

[71] Wang R, Wang D-t, Nagaumi H, et al.. Understanding the corrosion behavior by passive film evolution in Zn-containing Al-Si-Cu cast alloy [J]. Corrosion Science, 2022, 205: 110468

[72] Vacchi G S, Silva R, Plaine A H, et al.. Refill friction stir spot welded AA5754-H22/Ti-6Al-4V joints: Microstructural characterization and electrochemical corrosion behavior of aluminum surfaces [J]. Materials Today Communications, 2020, 22: 100759

[73] Martin F J, Cheek G T, O’grady W E, et al.. Impedance studies of the passive film on aluminium [J]. Corrosion Science, 2005, 47(12): 3187-3201

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