Suppression of serration of Al-Mg sheet by periodic indentation

Abstract

Abstract Al-Mg alloy sheets often exhibit surface defects, e.g., stretcher strain, after sheet metal forming. The surface defects are formed by nonuniform deformation due to the dynamic strain aging where serrations appear on stress-strain curves in tensile test. In order to suppress the nonuniform deformation, the authors propose periodic micro indentation on sheet surface in this study. Four Al-Mg alloy sheets were subjected to the tensile test after the indentation. Strain gauges on specimen surface were used to investigate the evolution of local strain. It is concluded that the periodic indentation can suppress nonuniform deformation.