چكيده به لاتين
Abstract:
The use of the equal channel angular rolling process, one of the methods of severe plastic deformation, high mechanical properties can be achieved. The aim of this study, was to determine the formability of sheets produced by the ECAR process at high temperature. In this study, the effect of equal channel angular rolling (ECAR) process temperature on the mechanical properties of 5083 aluminium alloy sheet was investigated. Therefore, ECAR process was performed at three different temperatures, ambient, 200℃ and 300℃. At ambient temperature up to 4 passes, at 200℃ up to 5 passes and at 300℃ up to 7 passes the equal channel angular rolling process was carried out on the samples. The investigation of mechanical properties such as yield strength, ultimate tensile strength and micro-hardness after each time passing the ECAR die set on samples at different temperatures showed that by applying the ECAR process at a specified temperature, the mechanical and microhardness properties of the samples were improved, while elongation to fracture was reduced. At ambient temperature after the three passes ECAR process yield strength, ultimate tensile strength and microhardness compared to the annealed sample increased by 94%, 19% and 52%, respectively. By comparing the mechanical properties of samples in a specified pass at different temperatures observed that by temperature increase, the yield strength, ultimate tensile strength and microhardness of the samples decreased in comparison with the ambient temperature, but the elongation to fracture as well as the formability was improved. Moreover, the determination of the forming limit diagrams (FLDs) using the experimental Nakazima test, showed that by applying the ECAR process at a specified temperature, the level of the FLDs moves downward which means is the reduction in the forming limits of ECARed samples. By comparing the FLDs of the samples, after the three time passing the ECAR die set at different temperatures were observed that the FLD0 at temperature of 200℃ and 300℃ compared to the ambient temperature increased by 5% and 20%, respectively, which this means is increasing the formability of samples by temperature increase.
Keywords: Severe Plastic Deformation (SPD), Equal Channel Angular Rolling (ECAR), Temperature, Mechanical Properties, Forming Limit Diagram (FLD).
