Effect of strain aging on stress fluctuation accompanied by tensile deformation in 5083 aluminum alloy plate

Abstract

It is well known that a pre-strain such as skin pass rolling is effective for the prevention of a strain marking accompanied by the forming. However, it has been pointed out that the formation of the strain marking depends on the time and the temperature history until the forming. In the present study, therefore, a 5083 aluminum alloy plate was tensile deformed and aged in order to investigate the influence of the strain aging on the stress fluctuation. Stress fluctuation resulted from the strain marking was generated with the lapse of strain aging time at any aging temperature, while the time required to the onset of stress fluctuation became long along with the rise in aging temperature. The amount of an increasing flow stress due to the strain aging increased monotonously with the rise in aging temperature and with the lapse of aging time. On the other hand, the critical strain required to the onset of stress fluctuation in the serration region decreased clearly when the strain aging was carried out at near 328 K, while there was no quantitative relation between the degree of time and strain of the strain aging and the amount of a decrease of the critical strain.