Effect of hot deformation on the microstructure of spray-formed 7055 aluminum alloy extruded plate

Abstract

The hot deformation behavior of spray-formed 7055 aluminum alloy extruded plate was studied under conditions of 300–450 °C and 0.01–25 s⁻¹ through a combination of Gleeble hot compression experiments and Deform-3D software simulations. The processing maps, simulation results, and calculation of residual dislocation density and stored energy were used to understand the microstructure evolution of the alloy. The results show that the optimum hot working conditions for the alloy lies within the high-temperature and low-strain rate region (400–450 °C, 0.01–1.0 s⁻¹), where the power dissipation coefficient η is the highest and the damage is the lowest. The unstable domain is concentrated in the high strain rate region (1.0–25 s⁻¹), which has the highest damage and is prone to cracking. Moreover, a slow heating and long duration heat-treatment prior to hot deformation was designed to solve the problem of formation of coarse grains and abnormal grain growth after solution treatment. This heat treatment can effectively reduce the residual dislocation density and stored energy, and promote the precipitation of Al₃Zr particles to hinder dislocation movement and pin grain boundaries, thereby inhibiting the static recrystallization during solution treatments.

Keywords

spray-formed 7055 aluminum alloy / hot deformation / Deform-3D software / damage value / coarse-grain

References

[1] ZhangP, LiY, LiuY, et al. . Analysis of the microhardness, mechanical properties and electrical conductivity of 7055 aluminum alloy [J]. Vacuum, 2020, 171: 109005

[2] BushR, KiyotaM, KiyotaC. Characterization of a friction stir weld in aluminum alloy 7055 using microhardness, electrical conductivity, and differential scanning calorimetry (DSC) [J]. Metallurgical and Materials Transactions A, 2016, 47(7): 3522-3532

[3] ZhangC, ZhangZ, LiuM, et al. . Effects of single- and multi-stage solid solution treatments on microstructure and properties of as-extruded AA7055 helical profile [J]. Transactions of Nonferrous Metals Society of China, 2021, 31(7): 1885-1901

[4] HeK, LiQ, LiuS, et al. . Influence of prestretching on quench sensitive effect of high-strength Al-Zn-Mg-Cu-Zr alloy sheet [J]. Journal of Central South University, 2021, 28(9): 2660-2669

[5] MondalC, MishraB, JenaP K, et al. . Effect of heat treatment on the behavior of an AA7055 aluminum alloy during ballistic impact [J]. International Journal of Impact Engineering, 2011, 38(8–9): 745-754

[6] JiaY, CaoF, NingZ, et al. . Influence of second phases on mechanical properties of spray-deposited Al-Zn-Mg-Cu alloy [J]. Materials & Design, 2012, 40536-540

[7] MondalC, MukhopadhyayA K, RaghuT, et al. . Tensile properties of peak aged 7055 aluminum alloy extrusions [J]. Materials Science and Engineering A, 2007, 454–455: 673-678

[8] SharmaM M, AmateauM F, EdenT J. Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions [J]. Journal of Alloys and Compounds, 2006, 416(1–2): 135-142

[9] WangF, XiongB, ZhangY, et al. . Microstructure and mechanical properties of spray-deposited Al-Zn-Mg-Cu alloy [J]. Materials & Design, 2007, 28(4): 1154-1158

[10] LiuH, LaverniaE J, RangelR H. Modeling of molten droplet impingement on a non-flat surface [J]. Acta Metallurgica et Materialia, 1995, 43(5): 2053-2072

[11] PuQ, JiaZ, KongY, et al. . Microstructure and mechanical properties of 2195 alloys prepared by traditional casting and spray forming [J]. Materials Science and Engineering A, 2020, 784: 139337

[12] JiaZ, XieZ, XiangK, et al. . Effect of heat treatment and extrusion processing on the microstructure and mechanical properties of spray formed 7055 alloy [J]. Materials Characterization, 2022, 183111619

[13] ChenC, HanW, QiM, et al. . Microstructure evolution and mechanical properties of an ultrahigh strength Al-Zn-Mg-Cu alloy via powder metallurgy and hot extrusion [J]. Journal of Central South University, 2021, 28(4): 1195-1205

[14] HuJ, WuX, BoH, et al. . Dislocation density model and microstructure of 7A85 aluminum alloy during thermal deformation [J]. Journal of Central South University, 2021, 28(10): 2999-3007

[15] ZhangQ, SunF, LiuM, et al. . Optimizing microstructure and mechanical properties of heat-treated Al-Zn-Mg-Cu alloy by indirect hot deformation technology [J]. Journal of Central South University, 2022, 29(11): 3544-3556

[16] ZangQ, YuH, LeeY S, et al. . Hot deformation behavior and microstructure evolution of annealed Al-7.9Zn-2.7Mg-2.0Cu (wt%) alloy [J]. Journal of Alloys and Compounds, 2018, 76325-33

[17] LinX, WuX, CaoL, et al. . The effects of heat treatment on the extrusion-induced inhomogeneity of spray-formed aluminum alloy 7055 [J]. Journal of Materials Research and Technology, 2023, 25: 2075-2087

[18] WuC, FengD, RenJ, et al. . Effect of non-isothermal retrogression and re-ageing on through-thickness homogeneity of microstructure and properties of Al-8Zn-2Mg-2Cu alloy thick plate [J]. Journal of Central South University, 2022, 29(3): 960-972

[19] GuoZ, ZhaoG, ChenX G. Effects of homogenization treatment on recrystallization behavior of 7150 aluminum sheet during post-rolling annealing [J]. Materials Characterization, 2016, 114: 79-87

[20] BachmannF, HielscherR, SchaebenH. Texture analysis with MTEX–free and open source software toolbox [J]. Solid State Phenomena, 2010, 160: 63-68

[21] ZhaoJ, DengY, TangJ, et al. . Influence of strain rate on hot deformation behavior and recrystallization behavior under isothermal compression of Al-Zn-Mg-Cu alloy [J]. Journal of Alloys and Compounds, 2019, 809: 151788

[22] LaasraouiA, JonasJ J. Prediction of steel flow stresses at high temperatures and strain rates [J]. Metallurgical Transactions A, 1991, 22(7): 1545-1558

[23] CastellanosJ, RieiroI, CarsíM, et al. . Analysis of adiabatic heating and its influence on the Garofalo equation parameters of a high nitrogen steel [J]. Materials Science and Engineering A, 2009, 517(1–2): 191-196

[24] PRASAD Y, RAO K, SASIDHAR S. Hot working guide: A compendium of processing maps[M]. ASM International, 2015.

[25] CASTELNAU O, UNGÁR T, MIROUX A, et al. Orientation dependent intragranular stored energy in polycrystalline TIIF steel [C]//Materials Science Forum. 2000, 321–324:720–725.

[26] Samet-MeziouA, EtterA L, BaudinT, et al. . Relation between the deformation sub-structure after rolling or tension and the recrystallization mechanisms of an IF steel [J]. Materials Science and Engineering A, 2008, 473(1–2): 342-354

[27] RheinheimerW, HoffmannM J. Grain growth transitions of perovskite ceramics and their relationship to abnormal grain growth and bimodal microstructures [J]. Journal of Materials Science, 2016, 51(4): 1756-1765

[28] YuT, LiB, MedjahedA, et al. . Impeding effect of the Al₃(Er, Zr, Li) particles on planar slip and intergranular fracture mechanism of Al-3Li-1Cu-0.1Zr-X alloys [J]. Materials Characterization, 2019, 147146-154

[29] LiuY, LinY C, LiH, et al. . Study of dynamic recrystallization in a Ni-based superalloy by experiments and cellular automaton model [J]. Materials Science and Engineering A, 2015, 626: 432-440

[30] ShenN, SamantaA, DingH. Microstructure simulations for orthogonal cutting via a cellular automaton model [J]. Procedia CIRP, 2017, 58: 543-548

[31] LiuS H, PanQ J, LiM J, et al. . Microstructure evolution and physical-based diffusion constitutive analysis of Al-Mg-Si alloy during hot deformation[J]. Materials & Design, 2019, 1275(19): 108181

[32] JaladurgamN R, KanjarlaA K. Hot deformation characteristics and microstructure evolution of Hastelloy C-276 [J]. Materials Science and Engineering A, 2018, 712240-254

[33] LinX, CaoL, WuX, et al. . Precipitation behavior of spray-formed aluminum alloy 7055 during high temperature aging [J]. Materials Characterization, 2022, 194112347

[34] WenK, LiX, XiongB, LiuH, et al. . Influence of minor Sc additions on grain refinement and microstructure characteristics of a high Zn-containing Al-Zn-Mg-Cu-Zr alloy [J]. Journal of Central South University, 2022, 29(3): 780-794