Microstructure, texture and interface integrity in sheets processed by Asymmetric Accumulative Roll-Bonding

DE GODOI, RENAN PEREIRA; CAMILO MAGALHÃES, DANIELLE CRISTINA; AVALOS, MARTINA; BOLMARO, RAUL EDUARDO; SORDI, VITOR LUIZ; KLIAUGA, ANDREA MADEIRA

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

ELSEVIER SCIENCE SA

Año: 2019

0921-5093

Accumulative Roll-Bonding (ARB) and Asymmetric Rolling (AR) techniques were combined to produceultrafine-grained aluminum sheets with the mechanical characteristics of a Severe Plastic Deformation (SPD)process. Temperature and number of bonding cycles were varied to promote grain refinement, texturerandomization and high-quality sheet bonding. Finite element simulation for a single pass was performed toclarify the strain distribution differences between symmetric and asymmetric roll -bonding. The microstructureand crystallographic texture were measured by Electron Backscatter Diffraction (EBSD) and X-ray diffraction.Hardness and tensile tests characterized strain distribution and bonding efficiency. A fine grain structure with amean grain size of 1.0 µm was achieved at 350 °C, whereas a coarser grain structure was obtained at 400 °C.The grain size and shape distribution were linked to enhancing the mechanical strength in a transversaldirection. During repeated bonding cycles at both temperatures, extra shear in the interfacial region yieldedfavorable homogeneous strain distribution and a weak shear texture across the sheet. Rotated-cube orientationwas the strongest component in both processing temperatures. To increase the interfacial strength, mainly onthe last bond interface, an extra 50% reduction step was added. This improved the adhesion in the last bondinginterface, and thus enhanced the ductility. These findings helped to provide a basis for determining theprocessing conditions for aluminum alloys.