Stress Induced Precipitation during Quenching of Aluminium Alloys

Abstract:

Quenching is an important step during age hardening of aluminium alloys. It significantly influences on microstructures, properties, residual stresses and component distortion. Due to high heat transfer, thermal stresses occur in quenched components. I.e., all premature precipitates during undercritical quenching form on condition of mechanical stresses. Opposite, quench sensitivity investigations, e.g. recording of continuous cooling precipitation diagrams, are usually performed in stress-free conditions and may therefore be incomplete. We have developed a new method of thermomechanical analysis and calorimetric reheating to investigate stress induced precipitation during quenching of aluminium alloys. For aluminium alloy 2024, it has been shown for the very first time that mechanical stresses during quenching also influence on quench-induced precipitation reactions.

• Periodical: Materials Science Forum (Volume 877)
• Pages: 159-165
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.877.159
• Online since: November 2016
• Authors: Julia Osten*, Christian Lux, Benjamin Milkereit, Michael Reich, Olaf Kessler
• Keywords: Aluminium Alloy, Differential Scanning Calorimetry, Elastic Deformation, Plastic Deformation, Precipitation, Quenching, Reheating, Thermomechanical Analysis

References

[1] M. Reich, O. Keßler, Quenching simulation of aluminum alloys including mechanical properties of the undercooled states, Matls Perf Charact. 1 (1) (2012) 104632.

DOI: 10.1520/mpc104632

[2] W.F. Hosford, S.P. Agrawal, Effect of stress during aging on the precipitation of θ' in Al-4 Wt pct Cu, Metall Trans A. 6 (3) (1975) 487–491.

DOI: 10.1007/bf02658406

[3] B. Skrotzki, G.J. Shiflet, E.A. Starke, On the effect of stress on nucleation and growth of precipitates in an Al-Cu-Mg-Ag alloy, MMTA. 27 (11) (1996) 3431–3444.

DOI: 10.1007/bf02595436

[4] A.W. Zhu, E.A. Starke, Stress aging of Al–xCu alloys: Experiments, Acta Materialia. 49 (12) (2001) 2285–2295.

DOI: 10.1016/s1359-6454(01)00119-7

[5] S. Fu, D. Yi, H. Liu, Y. Jiang, B. Wang, Z. Hu, Effects of external stress aging on morphology and precipitation behavior of θ" phase in Al-Cu alloy, T Nonferr Metal Soc. 24 (7) (2014) 2282–2288.

DOI: 10.1016/s1003-6326(14)63345-8

[6] D. Zohrabyan, B. Milkereit, O. Keßler, C. Schick, Precipitation enthalpy during cooling of aluminum alloys obtained from calorimetric reheating experiments, Thermochim Acta. 529 (2012) 51–58.

DOI: 10.1016/j.tca.2011.11.024

[7] M.J. Starink, B. Milkereit, Y. Zhang, P.A. Rometsch, Predicting the quench sensitivity of Al-Zn-Mg-Cu alloys: A model for linear cooling and strengthening, Materials and Design. 88 (2015) 958–971.

DOI: 10.1016/j.matdes.2015.09.058

[8] B. Milkereit, N. Wanderka, C. Schick, O. Keßler, Continuous cooling precipitation diagrams of Al-Mg-Si alloys, Mater Sci Eng A. 550 (2012) 87–96.

DOI: 10.1016/j.msea.2012.04.033

[9] B. Milkereit, O. Keßler, C. Schick, Recording of continuous cooling precipitation diagrams of aluminium alloys, Thermochim Acta. 492 (1-2) (2009) 73–78.

DOI: 10.1016/j.tca.2009.01.027

[10] M. Reich, O. Keßler, Mechanical properties of undercooled aluminium alloys and their implementation in quenching simulation, Mater Sci Technol. 28 (7) (2012) 769–772.

DOI: 10.1179/1743284711y.0000000085

[11] M. Reich, O. Kessler, Bauschinger effect in undercooled 6082 aluminium wrought alloy, HTM. 67 (5) (2012) 331–336.

DOI: 10.3139/105.110165

[12] J. Osten, B. Milkereit, C. Schick, O. Keßler, Dissolution and precipitation behaviour during continuous heating of Al-Mg-Si alloys in a wide range of heating rates: Materials, Mater. 8 (5) (2015) 2830–2848.

DOI: 10.3390/ma8052830

[13] I.J. Polmear, Light alloys: From traditional alloys to nanocrystals, 4th ed., Elsevier/ Butterworth-Heinemann, Oxford, (2005).

[14] S.C. Wang, M.J. Starink, Precipitates and intermetallic phases in precipitation hardening Al–Cu–Mg–(Li) based alloys, International Materials Reviews. 50 (4) (2005) 193–215.

DOI: 10.1179/174328005x14357