Microstructure and Mechanical Properties of Al-11.3Zn-3.2Mg-1.3Cu-0.2Zr-0.1Sr-xTi Extruded Aluminum Alloy with Different Aging Process

Abstract

The influences of adding different amount of Ti (0%, 0.39%, 0.87%) and three kinds of different aging processes (T6, T6I6, RRA) on the microstructure and properties of Al-11.3Zn-3.2Mg-1.3Cu-0.2Zr-0.1Sr were investigated. Results show that an appropriate amount of Ti can effectively inhibit grain growth and thus achieve the effect of grain refinement. The contribution of dislocation density and dislocation strengthening become the biggest when Ti content is 0.39%. At the same time, the intergranular corrosion depth is the lowest when Ti content is 0.39%. Among the three aging processes, the alloys reach the greatest hardness and tensile strength in T6I6. The biggest tensile strength reaches 716.77 MPa. However, when aging at RRA, the alloys obtain the greatest elongation, reaching 7.2%, as well as the good corrosion resistance.

Keywords

Al-Zn-Mg-Cu / Ti content / aging process / microstructure / properties

References

[1] Li Y, Deng Y, Fan S, et al. An In-Situ Study on the Dissolution of Intermetallic Compounds in the Al-Zn-Mg-Cu Alloy[J]. Journal of Alloys and Compounds, 2020, 829: 154 612.

[2] Ghosh A, Ghosh M, Seikh A H, et al. Phase Transformation and Dispersoid Evolution for Al-Zn-Mg-Cu Alloy Containing Sn During Homogenisation[J]. Journal of Materials Research and Technology, 2020, 9(1): 1-12.

[3] Zhao J, Deng Y, Tang J, et al. Effect of Gradient Grain Structures on Corrosion Resistance of Extruded Al-Zn-Mg-Cu Alloy[J]. Journal of Alloys and Compounds, 2020, 832: 154 911.

[4] Liu Y, Zhang C, Zhang X, et al. Understanding Grain Refinement of Sc Addition in a Zr Containing Al-Zn-Mg-Cu Aluminum Alloy from Experiments and First-Principles[J]. Intermetallics, 2020, 123: 106 823.

[5] Lin Y C, Zhu X H, Dong W Y, et al. Effects of Deformation Parameters and Stress Triaxiality on the Fracture Behaviors and Microstructural Evolution of an Al-Zn-Mg-Cu Alloy[J]. Journal of Alloys and Compounds, 2020, 832: 154 988.

[6] Zhao J, Liu Z, Bai S, et al. Effects of Natural Aging on the Formation and Strengthening Effect of G.P. Zones in a Retrogression and Re-Aged Al-Zn-Mg-Cu Alloy[J]. Journal of Alloys and Compounds, 2020, 829: 154 469.

[7] Chiu Y C, Du K T, Bor H Y, et al. The Effects of Cu, Zn and Zr on the Solution Temperature and Quenching Sensitivity of Al-Zn-Mg-Cu Alloys[J]. Materials Chemistry and Physics, 2020, 247: 122 853.

[8] Mondal C, Mukhopadhyay A K. On the Nature of T(Al₂Mg₃Zn₃) and S(Al₂CuMg) Phases Present in As-Cast and Annealed 7 055 Aluminum Alloy[J]. Materials Science and Engineering A, 2005, 391(1–2): 367-376.

[9] Sun Y, Johnson D R, Trumble K P. Effect of Zr on Recrystallization in a Directionally Solidified AA7050[J]. Materials Science and Engineering A, 2017, 700: 358-365.

[10] Xu X, Jin X, Liu Z, et al. Microstructure and Properties of a New Al-Cu-Mg-Zn-Zr-Ti Heat Resistant Aluminum Alloy[J]. Materials Research Express, 2020, 6: 126 5h8.

[11] Ding X, Meng L, Jiang L. Effect of Al-Ti-B Refiner on the Microstructure and Properties of ZL205A Aluminum Alloy[J]. Special Casting and Nonferrous Alloys, 2018, 38(07): 772-775.

[12] Ma X, Liu X, Ding H. A United Refinement Technology for Commercial Pure Al by Al-10Ti and Al-T-C Master Alloys[J]. Journal of Alloys and Compounds, 2009, 471(1–2): 56-59.

[13] Gao T, Zhang Y, Liu X. Influence of Trace Ti on the Microstructure. Age Hardening Behavior and Mechanical Properties of an Al-Zn-Mg-Cu-Zr Alloy[J]. Materials Science and Engineering A, 2014, 598: 293-298.

[14] Kheradmand A B, Mirdamadi S, Nategh S. Modified Age Hardening of Al-Zn-Mg-Cu with Minor Amount of Scandium and Zirconium[J]. Materials Research Express, 2019, 6: 086 529.

[15] Xu X, Shao H, Gao J, et al. Effect of SiC Film on Tensile Properties of Nanostructured Ti Produced by Compressive Deformation at Liquid-Nitrogen Temperature[J]. Materials Science and Engineering A, 2008, 493(1–2): 195-201.

[16] Youssef K M, Scattergood R O, Murty K L, et al. Nanocrystalline Al-Mg Alloy with Ultrahigh Strength and Good Ductility[J]. Scripta Materialia, 2006, 54(2): 251-256.

[17] Zhao Y H, Liao X Z, Jin Z, et al. Microstructures and Mechanical Properties of Ultrafine Grained 7 075 Al Alloy Processed by ECAP and Their Evolutions during Annealing[J]. Acta Materialia, 2004, 52(15): 4589-4599.