Changes in Mechanical Properties and Microstructure of Aluminum Alloy Sheets with Laser Cutting

Abstract

Because of the need for high-mix low-volume production, the use of CO₂ laser cutting is spreading rapidly in the sheet metal processing sector. Recently, aluminum alloy sheets of many kinds have found increased use in the industry because of social demands for environmental protection. We have investigated the heat effects of laser cutting materials by Electron Backscatter Diffraction and X-Ray Diffraction analysis. The specimens used were 1050 pure aluminum and 6022 aluminum alloy sheets processed by cold-rolling. In this report, we describes the distribution of plastic strain, the geometrically necessary dislocation density, and stored energy in the heat-affected zone from misorientations such as microscopic kernel average misorientation and grain orientation spread determined by EBSD measurement. Heat-affected zones showed reduced plastic strain, dislocation density, and stored energy with the recrystallization upon laser cutting. Therefore, mechanical properties such as hardness were also reduced.