Strain-rate sensitivity of ultrafine-grained materials

Abstract The strain-rate sensitivity of commercial purity Aluminium (Al 99.5) and of α-iron, with both conventional (CG) and ultrafine (UFG) grain sizes, are investigated by compression and tension tests at different temperatures. Microstructural investigations were performed before and after compression testing in order to investigate the microstructural stability. Pronounced strain rate sensitivity was found for UFG Al at room temperature as well as at elevated temperatures, while for UFG α-iron an enhanced strain-rate sensitivity was found only at elevated temperatures.