Effects of Yb/Zr micro-alloying on microstructure, mechanical properties and corrosion resistance of Al-Zn-Mg-Cu alloy

Abstract

The effects of Yb/Zr micro-alloying on the microstructure, mechanical properties, and corrosion resistance of an Al-Zn-Mg-Cu alloy were systematically investigated. Upon the addition of Yb/Zr to the Al-Zn-Mg-Cu alloy, the grain boundaries were pinned by high-density nanosized Al₃(Yb, Zr) precipitates during extrusion deformation, consequently, the average grain size was significantly reduced from 232.7 µm to 3.2 µm. This grain refinement contributed substantially to the improvement in both strength and elongation. The ultimate tensile strength, yield strength, and elongation of the Yb/Zr modified alloy increased to 705.3 MPa, 677.6 MPa, and 8.7%, respectively, representing enhancements of 16.2%, 19.3%, and 112.2% compared to the unmodified alloy. Moreover, the distribution of MgZn₂ phases along grain boundaries became more discontinuous in the Yb/Zr modified alloy, which effectively retarded the propagation of intergranular corrosion and improved the corrosion resistance.

Keywords

Al-Zn-Mg-Cu alloy / Yb/Zr micro-alloying / MgZn₂ phase / mechanical properties / corrosion resistance

References

[1] LiaoB, WuX-d, CaoL-f, et al.. The microstructural evolution of aluminum alloy 7055 manufactured by hot thermo-mechanical process. Journal of Alloys and Compounds, 2019, 796: 103-110[J]

[2] DursunT, SoutisC. Recent developments in advanced aircraft aluminium alloys. Materials & Design, 2014, 56: 862-871[J]

[3] LiS, DongH-g, ShiL, et al.. Corrosion behavior and mechanical properties of Al-Zn-Mg aluminum alloy weld. Corrosion Science, 2017, 123: 243-255[J]

[4] ChungT F, YangY L, ShiojiriM, et al.. Intrinsic twin boundary of η-MgZn₂ precipitates in the AA7050 aluminium alloy. Procedia Manufacturing, 2019, 37: 201-206[J]

[5] MeiL, YangM J, ChenX P, et al.. Precipitate evolution and properties of an Al-Zn-Mg-Cu alloy processed by thermomechanical treatment. Materials Science and Engineering A, 2023, 867144716[J]

[6] SongF-x, ZhangX-m, LiuS-d, et al.. The effect of quench rate and overageing temper on the corrosion behaviour of AA7050. Corrosion Science, 2014, 78: 276-286[J]

[7] ZhangM-h, LiuS-d, JiangJ-y, et al.. Effect of Cu content on quenching sensitivity relative to exfoliation corrosion susceptibility of Al-Zn-Mg-(Cu) alloys. Materials Characterization, 2022, 194112476[J]

[8] KairyS K, TurkS, BirbilisN, et al.. The role of microstructure and microchemistry on intergranular corrosion of aluminium alloy AA7085-T7452. Corrosion Science, 2018, 143: 414-427[J]

[9] HuangL P, ChenK H, LiS, et al.. Influence of high-temperature pre-precipitation on local corrosion behaviors of Al – Zn – Mg alloy. Scripta Materialia, 2007, 56(4): 305-308[J]

[10] ChengQ-s, YeL-y, HuangQ-m, et al.. Effect of two-stage overaging on microstructure and corrosion properties of an Al-Zn-Mg-Cu alloy. Journal of Materials Research and Technology, 2022, 20: 3185-3194[J]

[11] XiaoQ-f, HuangJ-w, JiangY-g, et al.. Effects of minor Sc and Zr additions on mechanical properties and microstructure evolution of Al-Zn-Mg-Cu alloys. Transactions of Nonferrous Metals Society of China, 2020, 30(6): 1429-1438[J]

[12] ShiY-j, PanQ-l, LiM-j, et al.. Effect of Sc and Zr additions on corrosion behaviour of Al-Zn-Mg-Cu alloys. Journal of Alloys and Compounds, 2014, 612: 42-50[J]

[13] SunF-f, NashG L, LiQ-y, et al.. Effect of Sc and Zr additions on microstructures and corrosion behavior of Al-Cu-Mg-Sc-Zr alloys. Journal of Materials Science & Technology, 2017, 33(9): 1015-1022[J]

[14] QianW, ZhaoY-t, KaiX-z, et al.. Characteristics of microstructural and mechanical evolution in 6111Al alloy containing Al₃(Er, Zr) nanoprecipitates. Materials Characterization, 2021, 178111310[J]

[15] WangY-c, WuX-d, YueL, et al.. Aging precipitation behavior and properties of Al-Zn-Mg-Cu-Zr-Er alloy at different quenching rates. Transactions of Nonferrous Metals Society of China, 2022, 32(4): 1070-1082[J]

[16] ZhangY, GaoK-y, WenS-p, et al.. Determination of Er and Yb solvuses and trialuminide nucleation in Al-Er and Al-Yb alloys. Journal of Alloys and Compounds, 2014, 590: 526-534[J]

[17] ZhaoY-x, LiH, LiuY, et al.. The microstructures and mechanical properties of a highly alloyed Al-Zn-Mg-Cu alloy: The role of Cu concentration. Journal of Materials Research and Technology, 2022, 18: 122-137[J]

[18] JiangL, ZhangZ-h, FuH-d, et al.. Corrosion behavior and mechanism of Al-Zn-Mg-Cu alloy based on the characterization of the secondary phases. Materials Characterization, 2022, 189111974[J]

[19] ShuW X, HouL G, ZhangC, et al.. Tailored Mg and Cu contents affecting the microstructures and mechanical properties of high-strength Al-Zn-Mg-Cu alloys. Materials Science and Engineering A, 2016, 657: 269-283[J]

[20] GazizovM, TeleshovV, ZakharovV, et al.. Solidification behaviour and the effects of homogenisation on the structure of an Al-Cu-Mg-Ag-Sc alloy. Journal of Alloys and Compounds, 2011, 509(39): 9497-9507[J]

[21] YangC, ZhangP, ShaoD, et al.. The influence of Sc solute partitioning on the microalloying effect and mechanical properties of Al-Cu alloys with minor Sc addition. Acta Materialia, 2016, 119: 68-79[J]

[22] HuangY-c, ZhangC-c, MaY-l, et al.. Effects of homogenization on the dissolution and precipitation behaviors of intermetallic phase for a Zr and Er containing Al-Zn-Mg-Cu alloy. Progress in Natural Science: Materials International, 2020, 30(1): 47-53[J]

[23] FangH C, LuoF H, ChenK H. Effect of intermetallic phases and recrystallization on the corrosion and fracture behavior of an Al-Zn-Mg-Cu-Zr-Yb-Cr alloy. Materials Science and Engineering A, 2017, 684: 480-490[J]

[24] PengG-s, ChenK-h, FangH-c, et al.. A study of nanoscale Al₃(Zr, Yb) dispersoids structure and thermal stability in Al-Zr-Yb alloy. Materials Science and Engineering A, 2012, 535: 311-315[J]

[25] HumphreysF J. The nucleation of recrystallization at second phase particles in deformed aluminium. Acta Metallurgica, 1977, 25(11): 1323-1344[J]

[26] NesE, RyumN, HunderiO. On the zener drag. Acta Metallurgica, 1985, 33(1): 11-22[J]

[27] SunF-f, NashG L, LiQ-y, et al.. Effect of Sc and Zr additions on microstructures and corrosion behavior of Al-Cu-Mg-Sc-Zr alloys. Journal of Materials Science & Technology, 2017, 33(9): 1015-1022[J]

[28] FangH C, ChaoH, ChenK H. Effect of recrystallization on intergranular fracture and corrosion of Al-Zn-Mg-Cu-Zr alloy. Journal of Alloys and Compounds, 2015, 622: 166-173[J]

[29] LiL-b, YuanT-c, YuanX-x. The microstructure regulation and property enhancement of directed energy deposited Al-Zn-Mg-Cu-Si-Zr alloy with various Zr contents. Materials Chemistry and Physics, 2023, 297127318[J]

[30] MaK-k, WenH-m, HuT, et al.. Mechanical behavior and strengthening mechanisms in ultrafine grain precipitation-strengthened aluminum alloy. Acta Materialia, 2014, 62: 141-155[J]

[31] HuZ-h, ZhangH, ZhuH-h, et al.. Microstructure, mechanical properties and strengthening mechanisms of AlCu₅MnCdVA aluminum alloy fabricated by selective laser melting. Materials Science and Engineering A, 2019, 759: 154-166[J]

[32] LiuX-b, ZhangD, WangH, et al.. Regulating solute partitioning utilized to decorate grain boundary for improving corrosion resistance in a model Al-Cu-Mg alloy. Corrosion Science, 2021, 181109219[J]

[33] SunY-w, WangZ-y, PanQ-l, et al.. Localized corrosion process of Al-Zn-Mg-Cu-Zr alloy: Transitions from pitting corrosion to intergranular corrosion. Journal of Central South University, 2023, 30(7): 2120-2132[J]

[34] ZhangY-l, YangH-f, HuangR-s, et al.. Investigation of microstructure and corrosion resistance of an Al-Zn-Mg-Cu alloy under various ageing conditions. Corrosion Science, 2024, 227111719[J]

RIGHTS & PERMISSIONS

Central South University