Abstract
In the present work, the precipitation hardening of 2024 and 7075 aluminum alloys is investigated as a function of cold rolling degree, ageing time and temperature using Vickers microhardness measurements and differential scanning calorimetry (DSC). It is found that a variation in such parameters can improve the hardness and plays an important role in the precipitation hardening process. At specific ageing temperature, the large cold rolled 7075 alloy exhibits two peaks of hardness. Moreover, for both alloys, the increment of hardness during ageing decreases with increasing the cold rolling degree. While in some cases microhardness measurements give impression that the precipitation reaction is slowed down by deformation, DSC analysis indicates that the precipitation is much accelerated since only a slight deformation decreases strongly the temperatures of reactions. However, the degree of cold rolling does not play a crucial role.
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Charaï, A., Walther, T., Alfonso, C., Zahra, A.M., Zahra, C.Y.: Co-existence of clusters, GPB zones, S″-, S′- and S-phases in an Al–0.9%Cu–1.4%Mg alloy. Acta Mater. 48, 2751–2764 (2000)
Colombo, S., Battaini, P., Airoldi, G.: Precipitation kinetics in Ag–7.5 wt.% Cu alloy studied by isothermal DSC and electrical-resistance measurements. J. Alloys Compd. 437, 107–112 (2007)
Cuisiat, F., Duval, P., Graf, R.: Etude des premiers stades de decomposition d’un alliage Al–Cu–Mg. Scr. Metall. 18, 1051–1056 (1984)
Deiasi, R., Adler, P.N.: Calorimetric studies of 7000 series aluminum alloys: I. Matrix precipitate characterization of 7075. Metall. Trans. A 8A, 1177–1183 (1977)
Develay, R.: Traitements thermiques des alliages d’aluminium. M1 290, pp. 13–26, Technique de l’Ingénieur (1995)
El-Baradie, Z.M., El-Sayed, M.: Effect of thermomechanical treatments on the properties of 7075 Al alloy. J. Mater. Process. Technol. 62, 76–80 (1996)
Khan, I.N., Starink, M.J., Yan, J.L.: A model for precipitation kinetics and strengthening in Al–Cu–Mg alloys. Mater. Sci. Eng. A 472, 66–74 (2008)
Kovarik, L., Court, S.A., Fraser, H.L., Mills, M.J.: GPB zones and composite GPB/GPBII zones in Al–Cu–Mg alloys. Acta Mater. 56, 4804–4815 (2008)
Lloyd, D.J., Chaturvedi, M.C.: A calorimetric study of aluminium alloy AA-7075. J. Mater. Sci. 17, 1819–1825 (1982)
Nagai, Y., Murayama, M., Tang, Z., Nonaka, T., Hono, K., Hasegawa, M.: Role of vacancy–solute complex in the initial rapid age hardening in an Al–Cu–Mg alloy. Acta Mater. 49, 913–920 (2001)
Nageswara Rao, P., Jayaganthan, R.: Effects of warm rolling and ageing after cryogenic rolling on mechanical properties and microstructure of Al 6061 alloy. Mater. Des. 39, 226–233 (2012)
Ning, A.L., Liu, Z.Y., Zeng, S.M.: Effect of large cold deformation after solution treatment on precipitation characteristic and deformation strengthening of 2024 and 7A04 aluminum alloys. Trans. Nonferr. Met. Soc. China 16, 1341–1347 (2006)
Ostermann, F.: Improved fatigue resistance of Al–Zn–Mg–Cu alloys through thermo-mechanical processing. Metall. Trans. 2, 2897–2902 (1971)
Papazian, J.M.: The effects of warm working on aluminum alloy 7075-T651. Mater. Sci. Eng. 51, 223–230 (1981)
Papazian, J.M.: Calorimetric studies of precipitation and dissolution kinetics in aluminum alloys 2219 and 7075. Metall. Trans. A 13A, 761–769 (1982)
Papazian, J.M.: Differential scanning calorimetry evaluation of retrogressed and Re-aged microstructures in aluminum alloy 7075. Mater. Sci. Eng. 79, 97–104 (1986)
Parel, T.S., Wang, S.C., Starink, M.J.: Hardening of an Al–Cu–Mg alloy containing type I and II S phase precipitates. Mater. Des. 31, S2–S5 (2010)
Park, J.K., Ardell, A.J.: Correlation between microstructure and calorimetric behavior of aluminum alloy 7075 and AI–Zn–Mg alloys in various tempers. Mater. Sci. Eng. A 114, 197–203 (1989)
Rack, H.J.: The influence of prior strain upon precipitation in a high-purity 6061 aluminum alloy. Mater. Sci. Eng. 29, 179–188 (1977)
Ringer, S.P., Hono, K.: Microstructural evolution and age hardening in aluminium alloys: atom probe field-ion microscopy and transmission electron microscopy studies. Mater. Charact. 44, 101–131 (2000)
Ringer, S.P., Sakurai, T., Polmear, I.J.: Origins of hardening in aged Al–Cu–Mg–(Ag) alloys. Acta Mater. 45, 3731–3744 (1997)
Shih, H., Ho, N., Huang, J.C.: Precipitation behaviors in Al–Cu–Mg and 2024 aluminum alloys. Metall. Mater. Trans. A, Phys. Metall. Mater. Sci. 27, 2479–2494 (1996)
Singh, S., Goel, D.B.: Influence of thermomechanical ageing on tensile properties of 2014 aluminium alloy. J. Mater. Sci. 25, 3894–3900 (1990)
Starink, M.J., Wang, S.C.: The thermodynamics of and strengthening due to co-clusters: general theory and application to the case of Al–Cu–Mg alloys. Acta Mater. 57, 2376–2389 (2009)
Starink, M.J., Gao, N., Yan, J.L.: The origins of room temperature hardening of Al–Cu–Mg alloys. Mater. Sci. Eng. A 387, 222–226 (2004)
Viana, F., Pinto, A.M.P., Santos, H.M.C., Lopes, A.B.: Retrogression and re-ageing of 7075 aluminium alloy: microstructural characterization. J. Mater. Process. Technol. 92, 54–59 (1999)
Wang, S.C., Starink, M.J.: Two types of S phase precipitates in Al–Cu–Mg alloys. Acta Mater. 55, 933–941 (2007)
Wang, S.C., Starink, M.J., Gao, N.: Precipitation hardening in Al–Cu–Mg alloys revisited. Scr. Mater. 54, 287–291 (2006)
Waterloo, G., Hansen, V., Gjønnes, J., Skjervold, S.R.: Effect of predeformation and preaging at room temperature in Al–Zn–Mg–(Cu, Zr) alloys. Mater. Sci. Eng. A 303, 226–233 (2001)
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Naimi, A., Yousfi, H. & Trari, M. Influence of cold rolling degree and ageing treatments on the precipitation hardening of 2024 and 7075 alloys. Mech Time-Depend Mater 17, 285–296 (2013). https://doi.org/10.1007/s11043-012-9182-0
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DOI: https://doi.org/10.1007/s11043-012-9182-0