Investigation on the Strain Behaviour of a Precipitation-Hardenable Aluminium Alloy through a Temperature Gradient Based Heat Treatment

Abstract:

In this work the strain behaviour of the heat-treated 6xxx series aluminium alloy AC170PX is investigated by a not conventional approach. Thanks to the low density combined with good mechanical properties, this aluminium alloy is often adopted for automotive applications. Despite these advantages, its formability at room temperature is low. In order to overcome this limit, a distribution of the material properties can be achieved by a local heat treatment (Tailored Heat Treated Blanks). In this context, to evaluate the effects of those parameters mainly affecting the precipitation hardening (aging temperature and aging time), a first experimental campaign was conducted using conventional furnace heat treatment in different conditions . Tensile tests were run with the aim of determining the flow and the aging curves of the heat treated specimens. Starting from these results, a not uniform heat treatment was designed using a Gleeble physical simulator Heat treatments based on a temperature gradient along the sample were performed. Then, tensile tests of the so heated specimens were carried out at room temperature. Through a digital image correlation system both the distribution and the evolution of the strain along the gauge length of the specimen were analysed in order to obtain the hardening/softening working conditions related to a specific heating cycle. These results were validated by the comparison with the data obtained from the first experimental campaign.

• Periodical: Key Engineering Materials (Volume 639)
• Pages: 361-368
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.639.361
• Online since: March 2015
• Authors: Gabriella di Michele*, Pasquale Guglielmi, Gianfranco Palumbo, Donato Sorgente
• Keywords: Aluminium, Metal Forming

References

[1] A. M. Ali, A. -F. Gaber, K. Matsuda, S. Ikeno Investigation and characterization of the nanoscale precipitation sequence and their kinetics in Al-1. 0% Mg2Si-0. 4 wt% Si-0. 5Cu (wt%) alloy, Materials Chemistry and Physics 147 (2014) 461-468.

DOI: 10.1016/j.matchemphys.2014.05.015

[2] H. Demir, S. Gündü, The effects of aging on machinability of 6061 aluminium alloy, Materials and Design 30 (2009) 1480–1483.

DOI: 10.1016/j.matdes.2008.08.007

[3] F. Ozturk, A. Sisman, S. Toros, S. Kilic, R.C. Picu, Influence of aging treatment on mechanical properties of 6061 aluminum alloy, Materials and Design 31 (2010) 972–975.

DOI: 10.1016/j.matdes.2009.08.017

[4] S. Esmaeili, D.J. Lloyd, Modeling of precipitation hardening in pre-aged AlMgSi(Cu) alloys, Acta Materialia 53 (2005) 5257–5271.

DOI: 10.1016/j.actamat.2005.08.006

[5] G. Palumbo, A. Piccininni, P. Guglielmi, D. Sorgente, LD. Scintilla and L. Tricarico, Application of the warm hydroforming process to the manufacturing of pre-aged 6xxx series components using a numerical/experimental approach, in: 15th Int. MetalForming Conference, Palermo (2014).

DOI: 10.4028/www.scientific.net/kem.622-623.701

[6] M. Geiger, M. Merklein, U. Vogt, Aluminum tailored heat treated blanks, Prod. Eng. Res. Devel. (2009) 3: 401–410.

DOI: 10.1007/s11740-009-0179-8

[7] H. Nguyen, M. Merklein, Improved Formability of Aluminum Alloys using Laser induced Hardening of Tailored Heat Treated Blanks, Physics Procedia 39 ( 2012 ) 318 – 326.

DOI: 10.1016/j.phpro.2012.10.044

[8] M. Merklein, W. Böhm, M. Lechner, Tailoring material properties of aluminum by local laser heat treatment, Physics Procedia 39 ( 2012 ) 232 – 239.

DOI: 10.1016/j.phpro.2012.10.034

[9] Y. Ning, Z. Yao, H. Guo, M.W. Fu, Structural-gradient-materials produced by gradient temperature heat treatment for dual-property turbine disc, Journal of Alloys and Compounds 557 (2013) 27-33.

DOI: 10.1016/j.jallcom.2013.01.011

[10] J. Min, J. Chen, X. Liang, J. Zhang, D. Wang, H. Li, Effects of gradient heat treatment on Te-rich CdZnTe crystal, Vacuum 86 (2012) 994-997.

DOI: 10.1016/j.vacuum.2011.09.017

[11] F. Ozturk, E. Esener, S. Toros, C. R. Picu, Effects of aging parameters on formability of 6061-O alloy, Materials and Design 31 (2010) 4847–4852.

DOI: 10.1016/j.matdes.2010.05.050

[12] Y. Aouabdia, A. Boubertakh, S. Hamamda, Precipitation kinetics of the hardening phase in two 6061 aluminium alloys, Materials Letters 64 (2010) 353–356.

DOI: 10.1016/j.matlet.2009.11.014