Ultrahigh strength and improved electrical conductivity in an aging strengthened copper alloy processed by combination of equal channel angular pressing and thermomechanical treatment

Abstract

In this paper, equal channel angular pressing and thermomechanical treatment was employed to improve the strength and electrical conductivity of an aging strengthened Cu-Ti-Cr-Mg alloy, and the microstructure and properties of the alloy were investigated in detail. The results showed that the samples deformed by the combination of cryogenic equal channel angular pressing (ECAP) and rolling had good comprehensive properties after aging at 400 °C. The tensile strength of the peak-aged and over-aged samples was 1120 MPa and 940 MPa, with their corresponding electrical conductivity of 14.7%IACS and 22.1%IACS, respectively. ECAP and cryogenic rolling introduced high density dislocations, leading to the inhibition of the softening effects and refinement of the grains. After a long time aging at 400 °C, the alloy exhibited ultra-high strength with obvious increasing electrical conductivity. The high strength was attributed to the synergistic effect of work hardening, grain refinement strengthening and precipitation strengthening. The precipitation of a large amount of Ti atoms from the matrix led to the high electrical conductivity of the over-aged sample.

Keywords

Cu-Ti alloy / equal channel angular pressing / rolling / aging treatment / high strength

References

[1] LiuW-j, ChenX, AhmadT, et al. . Microstructures and mechanical properties of Cu-Ti alloys with ultrahigh strength and high ductility by thermomechanical treatment [J]. Materials Science and Engineering A, 2022, 835: 142672

[2] HuangL, CuiZ-s, MengX-p, et al. . Effect of trace alloying elements on the stress relaxation properties of high strength Cu-Ti alloys [J]. Materials Science and Engineering A, 2022, 846143281

[3] LiuJ, WangX-h, GuoT-t, et al. . Microstructure and properties of Cu-Ti-Ni alloys [J]. International Journal of Minerals, Metallurgy, and Materials, 2015, 22(11): 1199-1204

[4] SemboshiS, KonnoT J. Effect of aging in hydrogen atmosphere on electrical conductivity of Cu-3at.% Ti alloy [J]. Journal of Materials Research, 2008, 23(2): 473-477

[5] HanS Z, ChoiE A, LimS H, et al. . Alloy design strategies to increase strength and its trade-offs together [J]. Progress in Materials Science, 2021, 117100720

[6] SoffaW A, LaughlinD E. High-strength age hardening copper-titanium alloys: Redivivus [J]. Progress in Materials Science, 2004, 49(34): 347-366

[7] LiC, WangX-h, LiB, et al. . Effect of cold rolling and aging treatment on the microstructure and properties of Cu-3Ti-2Mg alloy [J]. Journal of Alloys and Compounds, 2020, 818152915

[8] HuangL, CuiZ-s, MengX-p, et al. . Effects of microelements on the microstructure evolution and properties of ultrahigh strength Cu-Ti alloys [J]. Materials Science and Engineering A, 2021, 823141581

[9] WuY-k, LiY, LuJ-y, et al. . Effects of pre-deformation on precipitation behaviors and properties in Cu-Ni-Si-Cr alloy [J]. Materials Science and Engineering A, 2019, 742501-507

[10] BeyerleinI J, TóthL S. Texture evolution in equal-channel angular extrusion [J]. Progress in Materials Science, 2009, 54(4): 427-510

[11] AsanoM, YuasaM, MiyamotoH. Effects of stacking fault energy and solute atoms on microstructural evolution of Cu, Ag and Cu-Al alloys processed by equal channel angular pressing [J]. Materials Science and Engineering A, 2021, 803: 140716

[12] MaM-z, LiZ, QiuW-t, et al. . Microstructure and properties of Cu-Mg-Ca alloy processed by equal channel angular pressing [J]. Journal of Alloys and Compounds, 2019, 78850-60

[13] GuoT-b, QianD-c, HuangD-w, et al. . Deformation microstructure and properties control of Cu-0.6Cr alloy in cryo-equal channel angular pressing [J]. Journal of Central South University, 2023, 30(7): 2094-2106

[14] JiaH-l, BjørgeR, CaoL-f, et al. . Quantifying the grain boundary segregation strengthening induced by post-ECAP aging in an Al-5Cu alloy [J]. Acta Materialia, 2018, 155: 199-213

[15] HuY-f, ZhangY-b, ZengQ, et al. . Achieving nanoscale Al₂Cu dispersoids in wrought Al-4.5wt.%Cu alloy by semi-solid isothermal treatment and post room-temperature ECAP [J]. Materials Letters, 2021, 305: 130787

[16] YangZ-j, WangK-k, YangYan. Optimization of ECAP-RAP process for preparing semisolid billet of 6061 aluminum alloy [J]. International Journal of Minerals, Metallurgy and Materials, 2020, 27(6): 792-800

[17] JiaD-s, HeT, SongM, et al. . Microstructure evolution of 7050 Al alloy fasteners during cold upsetting after equal channel angular pressing [J]. Journal of Central South University, 2023, 30(11): 3682-3695

[18] LiuX-w, BianL-p, TianF, et al. . Microstructural evolution and mechanical response of duplex Mg-Li alloy containing particles during ECAP processing [J]. Materials Characterization, 2022, 188111910

[19] SunC, LiuH, WangC, et al. . Anisotropy investigation of an ECAP-processed Mg-Al-Ca-Mn alloy with synergistically enhanced mechanical properties and corrosion resistance [J]. Journal of Alloys and Compounds, 2022, 911165046

[20] ZhangX-p, WangH-x, BianL-p, et al. . Microstructure evolution and mechanical properties of Mg-9Al-1Si-1SiC composites processed by multi-pass equal-channel angular pressing at various temperatures [J]. International Journal of Minerals, Metallurgy and Materials, 2021, 28(12): 1966-1975

[21] LiuY, LiW, LiY-yuan. Microstructure and mechanical properties of ZE10 magnesium alloy prepared by equal channel angular pressing [J]. International Journal of Minerals, Metallurgy, and Materials, 2009, 16(5): 559-563

[22] SakaiT, BelyakovA, KaibyshevR, et al. . Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions [J]. Progress in Materials Science, 2014, 60130-207

[23] ZahidG H, HuangY, PrangnellP B. Microstructure and texture evolution during annealing a cryogenic-SPD processed Al-alloy with a nanoscale lamellar HAGB grain structure [J]. Acta Materialia, 2009, 57(12): 3509-3521

[24] GuoF, DongH-p, HuangW-j, et al. . Nanocrystalline structure fabricated by cryogenic temperature rolling of AA 2099 aluminum alloy [J]. Journal of Alloys and Compounds, 2021, 864: 158293

[25] SunJ-p, YangZ-q, HanJ, et al. . High strength and ductility AZ91 magnesium alloy with multi-heterogenous microstructures prepared by high-temperature ECAP and short-time aging [J]. Materials Science and Engineering A, 2018, 734485-490

[26] MagalhãesD C C, KliaugaA M, HupaloM F, et al. . The influence of Cryo-ECAP and aging on the microstructure and mechanical behavior of AA6061 Al alloy [J]. Materials Science and Engineering A, 2019, 768: 138485

[27] RominiyiA L, OluwasegunK M, OlawaleJ O, et al. . Effect of post-ECAP aging on the microstructure, hardness and impact behaviour of 6061 Al alloy [J]. Materials Today: Proceedings, 2021, 381031-1034

[28] PurcekG, YanarH, DemirtasM, et al. . Optimization of strength, ductility and electrical conductivity of Cu-Cr-Zr alloy by combining multi-route ECAP and aging [J]. Materials Science and Engineering A, 2016, 649: 114-122

[29] WangX, XiaoZ, MengX-p, et al. . Microstructure and properties evolution of Cu-Ti-Cr-Mg alloy during equal channel angular pressing at room temperature and cryogenic temperature [J]. Journal of Alloys and Compounds, 2022, 927: 166940

[30] LiR, XiaoZ, LiZ, et al. . Work hardening behavior and microstructure evolution of a Cu-Ti-Cr-Mg alloy during room temperature and cryogenic rolling [J]. Materials, 2023, 16(1): 424

[31] ValievR Z, LangdonT G. Principles of equal-channel angular pressing as a processing tool for grain refinement [J]. Progress in Materials Science, 2006, 517881-981

[32] SongD, WangG-w, ZhouZ-k, et al. . Developing a high-strength Al-11Si alloy with improved ductility by combining ECAP and cryorolling [J]. Materials Science and Engineering A, 2020, 773138880

[33] BanY-j, GengY-f, HouJ-r, et al. . Properties and precipitates of the high strength and electrical conductivity Cu-Ni-Co-Si-Cr alloy [J]. Journal of Materials Science & Technology, 2021, 931-6

[34] MaM-z, XiaoZ, MengX-p, et al. . Effects of trace calcium and strontium on microstructure and properties of Cu-Cr alloys [J]. Journal of Materials Science & Technology, 2022, 112: 11-23

[35] ZengW, XieJ-w, ZhouD-s, et al. . Bulk Cu-NbC nanocomposites with high strength and high electrical conductivity [J]. Journal of Alloys and Compounds, 2018, 745: 55-62

[36] NagarjunaS, BalasubramanianK, SarmaD S. Effect of Ti additions on the electrical resistivity of copper [J]. Materials Science and Engineering A, 1997, 225(1–2): 118-124

[37] GhoshG, MiyakeJ, FineM E. The systems-based design of high-strength, high-conductivity alloys [J]. JOM, 1997, 49(3): 56-60

[38] MakiK, ItoY, MatsunagaH, et al. . Solid-solution copper alloys with high strength and high electrical conductivity [J]. Scripta Materialia, 2013, 68(10): 777-780

[39] ChangS-y, ChenC-f, LinS J, et al. . Electrical resistivity of metal matrix composites [J]. Acta Materialia, 2003, 51(20): 6291-6302

[40] AndrewsP V, WestM B, RobesonC R. The effect of grain boundaries on the electrical resistivity of polycrystalline copper and aluminium [J]. Philosophical Magazine, 1969, 19(161): 887-898

[41] BasinskiZ S, DugdaleJ S, HowieA. The electrical resistivity of dislocations [J]. Philosophical Magazine, 1963, 8(96): 1989-1997

[42] MaM-z, LiZ, XiaoZ, et al. . Microstructure and properties of Cu-Ni-Co-Si-Cr-Mg alloys with different Si contents after multi-step thermo-mechanical treatment [J]. Materials Science and Engineering A, 2022, 850143532