Paper Title
Effect of Cold Rolling on Microstructure, Tensile Properties and Fatigue Crack Propagation of Aa 5052 Aluminum Alloy

Abstract
The effect of cold rolling on microstructure, tensile properties and fatigue crack propagation of AA 5052 aluminum alloy was investigated by optical microscope, tensile and fatigue tests. The AA 5052 aluminum ally was homogenized at temperature of 470ºC for 6 h and then applied to cold rolling with the various thickness reduction of 15, 30 and 45%. The results showed that the grains size in longitudinal direction were reduced with the enhancement of thickness reduction, whereas the grains in long transvers direction become elongated along the rolling direction. Due to work hardening effect, the tensile and yield strength were enhanced with increasing the percentage of thickness reduction. However, the ductility was reduced. The fatigue crack propagation versus stress intensity factor range were investigated in the Paris’s region. The different gains structure led to various of fatigue crack propagation. The fatigue crack propagation was increased with increasing the percentage of thickness reduction. Furthermore, the Paris constant C was enhanced when the thickness reduction was increased. However, the Paris exponent n was reduced. Keywords- Cold Rolling, Microstructure, Tensile Properties, Fatigue Crack Propagation, AA 5052 Aluminum Alloy.