Mechanical properties and microstructural evolution during multi-pass ECAR of Al 1100–O alloy

The main objective of this work is to achieve ultra-fine grained structures within the pure aluminum sheet via equal channel angular rolling (ECAR). An attempt has been made to investigate the microstructural evolution and mechanical properties of the processed specimens in terms of process pass numbers and routes. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) examination showed ultra-fine grains (UFGs) with the average grain size of 0.85, 0.34 μm for the seventh pass, respectively. Yield and tensile strengths and microhardness of specimens were significantly increased upon the first pass; however, elongation was dramatically reduced. Subsequent process cycles caused no considerable improvement on the mechanical properties.

► Mechanical properties and microstructural evolution of ECAR of Al 1100–O alloy were studied.
► Grain refinement mechanism of ECARed specimens was evaluated.
► The average grain size after the seven passes of ECAR was about 0.85 μm.
► ECARed specimens have a higher strength and hardness and lower ductility.