Observation of Grain-Size Effect in Serration of Aluminum Alloy

Serration phenomena of AA5083 alloys with various crystal grain sizes during tensile tests were visualized using Electronic Speckle Pattern Interferometry. The behavior of deformation band during the plastic deformation associated with the serration was investigated by a dynamic observation of the images of displacement contours. The characteristic in the serrated curve varied depending on the grain size of specimen and the applied total strain at which the deformation band appeared. The occurrence and propagation processes of the deformation band observed in the displacement contours were investigated being compared with the serrated curve in the load. The correlation between the band propagation and the serrated curve, and the difference in the behavior of band propagation by the grain size were discussed based on the variations in the magnitude of the load drop and the velocity of the moving deformation band.