Author/Authors :
Rassa, Mahnoush Department of Mechanical Engineering - College of Engineering - University of Tehran, Tehran, Iran , Azadkoli, Geonik Department of Mechanical Engineering - College of Engineering - University of Tehran, Tehran, Iran , Eftekhari, Mohammad Department of Mechanical Engineering - College of Engineering - University of Tehran, Tehran, Iran , Fata, Ali Department of Mechanical Engineering - Faculty of Engineering - University of Hormozgan, Bandar Abbas, Iran , Faraji, Ghader Department of Mechanical Engineering - College of Engineering - University of Tehran, Tehran, Iran
Abstract :
In this study, equal channel angular pressing (ECAP) process with an additional expansion-extrusion stage named expansion-extrusion equal channel angular pressing (EECAP) process is utilized for producing bulk ultrafine grained (UFG) Mg–9Al–1Zn magnesium alloy. In this process, cyclic expansion-extrusion (CEE) and equal channel angular pressing (ECAP) processes are combined. AZ91 magnesium alloy was used for this experiment. An FEM simulation was performed to calculate the compressive hydrostatical stress. Furthermore, microstructural and mechanical properties were investigated. The experimental findings revealed that the ductility of the sample remains almost constant (0.03% drop) while ultimate tensile strength increased about 30%. The average value of microhardness improved from 48 Hv to 65 Hv (35%) and grain size refined from 144 µm to 3.4 µm. Despite the expansion part of the die, there is no need for back pressure. Another advantage of this new method is maintaining ductility while strengthening.
Keywords :
severe plastic deformation , AZ91 alloy , EECAP , Ultrafine grained metals
