Relationship between mechanical properties and microstructural response of 6061-T6 aluminum alloy impacted at elevated temperatures

• 6061-T6 alloy is impacted at temperatures ranging from 100 to 350 °C and strain rates in the range of 1 × 103 to 5 × 103 s−1.
• The flow stress increases with increasing strain rate or decreasing temperature.
• The higher flow stress is the result of a smaller grain size and a smaller dislocation cell size.
• The stacking fault energy of the deformed specimens has a value of 145.78 mJ/m2.

The high temperature impact properties and microstructural evolution of 6061-T6 aluminum alloy are investigated at temperatures ranging from 100 to 350 °C and strain rates ranging from 1 × 103 to 5 × 103 s−1 using a compressive split-Hopkinson pressure bar (SHPB) system. It is found that the flow response and microstructural characteristics of 6061-T6 aluminum alloy are significantly dependent on the strain rate and temperature. The flow stress and strain rate sensitivity increase with increasing strain rate or decreasing temperature. Moreover, the temperature sensitivity increases with both increasing strain rate and increasing temperature. The flow stress–strain response of the present 6061-T6 alloy specimens can be adequately described by the Zerilli–Armstrong fcc model. The grain size and dislocation cell size increase significantly with a decreasing strain rate or an increasing temperature. The higher flow stress is the result of a smaller grain size and smaller dislocation cell size. The stacking fault energy of the deformed specimens has a value of 145.78 mJ/m2.