Enhanced formability and hardness of AA2195-T6 during electromagnetic forming

Abstract

AA2195 sheets treated by artificial aging to an ultra-high strength were subjected to electromagnetic forming (EMF) to overcome the distortion of formed components during heat treatment. The deformation behavior and corresponding strengthening effect of a conical-shape workpiece were evaluated by strain analysis and Vickers hardness testing, respectively. The limiting dome height (LDH) and limiting effective strain of the conical workpiece during electromagnetic bulging were 26.7 mm and 46.3%, respectively. Hardness in the undeformed area of the conical workpiece was 180 HV, which increased with increased deformation during electromagnetic bulging, reaching 200 HV at the effective strain of 35%. Microstructure characterization showed that grain distribution increased in uniformity with increase in strain, accompanied by small and equiaxed grains. Dislocation density and low-angle grain boundaries increased with increasing strain, which improved the strength of the bulged specimen. Texture evolution indicated that the {110}<112>orientation of the Brass texture component increased significantly as the deformation increased. Considerable helical dislocations were formed during electromagnetic bulging, which led to the improved hardness with an increase in strain. This study proves the feasibility of forming ultra-high-strength aluminum alloys at room temperature.