Physical simulation of asymmetric sheet rolling process by multicycle shear-compression testing

Abstract

Abstract Asymmetric sheet rolling process is one of the methods of severe plastic deformation which can be used to improve the microstructure and mechanical properties of metallic materials. The mechanism of severe plastic deformation during asymmetric rolling comes from synergistic combination of compressive strain and very significant shear strain. Laboratory simulation of stress-strain state and microstructure evolution, which are similar to that occurring during asymmetric sheet rolling process, is very important for design of technologies of producing fine grained materials. Shear-compression testing of materials is complicated by the fact that a state of large equivalent strain with dominant shear strain is not easily achievable. This paper presents the novel technique of laboratory simulation of asymmetric sheet rolling process by multicycle shear-compression testing at room temperature with equivalent strain e=1…5. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. Height of the specimen was 50 mm, section dimensions were 25×25 mm, gauge thickness was 5.0 mm and gauge width was 6.0 mm. The specimen provided dominant shear strain in an inclined gauge-section. The level of shear strain and equivalent strain was controlled through adjustment of the height reduction of the specimen, load application direction and number of cycles of shear-compression. Aluminium alloy Al-6.2Mg-0.7Mn was used as a material for specimen. FE simulation and analysis of the stress-strain state were performed. The microstructure of the specimen after multicycle shear-compression testing with equivalent strain e=1…5 was examined by optical and scanning electron microscope. The results of investigation can be used to optimize the asymmetric rolling process to improve microstructure and mechanical properties of aluminium sheets.