Behaviour of Al6061-T6 alloy at different temperatures and strain-rates: Experimental characterization and material modelling

The simulation of impact scenario against a structure requires the use of material models able to reproduce all aspects of the mechanical behaviour of the involved materials; plastic flow is one of the main aspects to be reproduced. In more detail, attention has to be paid to the investigation of strain-rate and temperature sensitivities, as well as their interaction, which necessitates the use of a reverse engineering approach. The present paper mainly focuses on the tensile behaviour and an ad-hoc testing campaign was performed on cylindrical dog-bone specimens made in Al6061T6 at different temperatures and strain-rates extending the range up to a level where, at present, there is a lack in the scientific literature. The thermal softening effect was investigated in quasi-static as well as in dynamic loading conditions from room temperature up to 400 °C; while the material strength dependence on the strain-rate was studied up to 104 s−1 on miniaturized samples. Microstructure analyses were performed to better investigate the mechanical response at different loading conditions. The parameters of the Johnson-Cook model were identified starting from experimental data via a numerical inverse approach based on FEM simulations. These parameters can be used for simulations of extreme loading scenario like ballistic impact events.