High cycle fatigue behavior of Al1070 alloy severely deformed by equal channel angular pressing process

Abstract

In the present work, equal channel angular pressing of commercial pure aluminum 1070 was performed up to 4 passes using route B_c. For equal channel angular pressing operation, a suitable die set was designed and manufactured. X-ray diffraction analysis was used to determine the microstructure of the equal channel angular pressing-ed material. The fracture surface morphology and microstructure after fatigue were investigated by scanning electron microscopy. Mechanical properties of the equal channel angular pressing-ed material were evaluated by hardness and tension tests. Also, cyclic deformation behavior of severe plastic deformation Al1070 has been studied and results show a significant variation in hardness, ultimate strength and fatigue properties in high cycle fatigue life. Coefficient of fatigue strength σ′_f and Bridgman correction factor have been obtained by S-N curve and tension test specimens, respectively, and compared before and after equal channel angular pressing process. Also an useful relation has been derived between fatigue life (N_f) and stress amplitude (σ_a) in high cycle fatigue region. Results indicated that there was not clear relation between fatigue strength coefficient and true corrected fracture stress in this case.

Keywords

ECAP high cycle fatigue commercial pure aluminum

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