Comparison of Tensile Flow Behavior of Hot Uni-directional Accumulative Roll Bonded with Hot Cross Accumulative Roll Bonded AA۵۰۸۳ Sheets

Previous studies show that the routes of rolling cycles in accumulative roll bonding considerably affect the microstructure and mechanical properties of some materials such as aluminum alloy sheets. The most common methods are Uni-directional Accumulative Roll Bonding (UARB) and Cross Accumulative Roll Bonding (CARB). In UARB process all rolling cycles are conducted along the initial rolling direction of the sheet. In CARB process, the sheet is rotated ۹۰˚ before each rolling cycle. In the present work, these processes were applied with intermediate heating at ۴۰۰˚C on initially annealed AA۵۰۸۳ sheets and tensile test was conducted along initial rolling direction on initially annealed, UARBed and CARBed sheets. Results indicated that both UARB and CARB increase the strength in cost of loss of ductility. Also, CARB increases the strength and decreases the ductility more than UARB such that the surface area under the flow curve increases with CARB. As AA۵۰۸۳ undergoes Portevin Le-Chatelier (PLC) effect, it has been figured out that the intensity and number of flow curve serrations decreases by applying UARB or CARB caused by the loss of mobile dislocations as a result of mechanical working. Also the reason of existence of more intense serrations in the CARB flow curves than UARB ones is attributed to the activation of new slip systems by applying the loading in two directions.

Keywords:

Accumulative Roll Bonding (ARB) , Uni-directional Accumulative Roll Bonding (UARB) , Cross Accumulative Roll Bonding (CARB) , Tensile Test , AA۵۰۸۳ Sheets