Quench sensitivity of toughness in an Al alloy: direct observation and analysis of failure initiation at the precipitate free zone


Morgeneyer, T.F., Starink, M.J., Wang, S.C. and Sinclair, I. (2008) Quench sensitivity of toughness in an Al alloy: direct observation and analysis of failure initiation at the precipitate free zone. Acta Materialia, 56, (12), 2872-2884. (doi:10.1016/j.actamat.2008.02.021).

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Description/Abstract

Analysis of toughness in 6156 Al-Mg-Si-Cu sheet has been performed using enhanced Kahn tear tests on samples quenched at different rates. Crack initiation energies were hardly affected by changing water quench temperature from 20°C to 60°C; however a significant reduction was evident on air cooling. Crack propagation energy was reduced for both 60°C water quenched and air cooled materials. Observation of failure initiation through synchrotron radiation computed tomography (SRCT), for the 60°C water quenched material revealed failure ahead of the crack tip of grain boundaries oriented at 45° to the main loading axis and crack “tongues” extending into the material ahead of the main crack. Failure was predominantly intergranular. Fractographic assessment revealed predominantly voiding and shear decohesion in the 20°C water quenched material. With the aid of the new findings past models on the influence of precipitate free zone parameters on toughness have been revised

Item Type: Article
Additional Information: Acknowledgements: The authors would like to acknowledge Alcan CRV for financial support and material supply, and Frederic Bron and Bernard Bes for technical discussion. We would also like to thank Jean-Yves Buffière for support in micro-computed tomography.
ISSNs: 1359-6454 (print)
Keywords: AA6156, quench sensitivity, precipitate free zone, synchrotron radiation computed tomography, intergranular failure, aerospace, toughness, weldable, aluminium, precipitation, fractography, sem, tem
Subjects: T Technology > TN Mining engineering. Metallurgy
Divisions: University Structure - Pre August 2011 > School of Engineering Sciences > Engineering Materials & Surface Engineering
ePrint ID: 50314
Date Deposited: 14 Feb 2008
Last Modified: 15 Aug 2014 08:19
URI: http://eprints.soton.ac.uk/id/eprint/50314

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