High Strain Rate Behaviour of AA7075 Aluminum Alloy at Different Initial Temper States

Abstract:

The aim of this work is to study the mechanical properties of alloy AA7075 in both T6 and O temper states, in terms of visco-plastic and fracture behavior. Tension and compression tests were carried out starting from the quasi-static loading condition 10^-3 up to strain rates as high as 2 x 10³ s^-1. The high strain rate tests were performed using a Split Hopkinson Tension-Compression Bar (SHTCB) apparatus. The tensile specimens were also subjected to micro-fractography analysis by Scanning Electronic Microscope (SEM) to evaluate the characteristics of the fracture. The results show a different behavior for the two temper states: AA7075-O showed a significant sensitivity to strain rate, with a ductile behavior and a fracture morphology characterized by coalescence of microvoids, whilst AA7075-T6 is generally characterized by a less ductile behaviour, both as elongation at break and as fracture morphology. Brittle cleavage is accentuated with increasing strain rate. The Johnson-Cook viscoplastic model wad also used to fit the experimental data with an optimum matching.

• Periodical: Key Engineering Materials (Volumes 651-653)
• Pages: 114-119
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.651-653.114
• Online since: July 2015
• Authors: Marco Sasso*, Archimede Forcellese, Michela Simoncini, Dario Amodio, Edoardo Mancini
• Keywords: Aluminium Alloy, High Strain Rate, Inverse Calibration, SEM, Split Hopkinson Bar

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