Microstructural evolution and mechanical properties of accumulative roll bonded interstitial free steel

Severe deformation processing is an emerging technique, for the production of submicron grain structures in metallic material, which involves plastic deformation to ultra-high strains. An ultra-fine grained (UFG) material was prepared from an IF steel sheet using Accumulative Roll Bonding (ARB) process. After initial preparing to achieve good sheet bonding, ten cycles of ARB at 500 °C were successfully performed. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used for the characterization of subgrain and grain structures of ARB processed samples. The mechanical attributes after rolling and cooling were examined. Also, the fracture surfaces were studied by Scanning Electron Microscopy (SEM). It was concluded that metal’s tensile strengths increased by 334% while the ductility dropped from a pre-rolled value of 50.5% to 2.6%. The rolling process was stopped in cycle 10, when cracking of the edges became pronounced.