Structural stability of ultra-fine grained magnesium alloys processed by equal channel angular pressing

7th International Conference on Nanomaterials by Severe Plastic Deformation

Janeek, M.^1 ; Kraják, T.^1 ; Minárik, P.^1 ; íek, J.^1 ; Stráská, J.^1 ; Stráský, J.^1

Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, Praha 2

121 16, Czech Republic^1

关键词: Dislocation densities;    Electron back scatter diffraction;    Magnesium alloys AZ31;    Micro-structure evolutions;    Microscopic mechanisms;    Microstructure stability;    Structural stabilities;    Ultrafine grained structure;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/194/1/012052/pdf
DOI  :  10.1088/1757-899X/194/1/012052

来源: IOP

【 摘 要 】

Structural stability of two magnesium alloys AZ31 (MgAlZn) and AX41 (MgAlCa) processed by equal channel angular pressing is investigated. The mechanical properties, microstructure evolution and dislocation density were studied by microhardness, electron back scatter diffraction and positron annihilation spectroscopy, respectively. The loss of microstructure stability at high temperatures and the coarsening of the ultrafine-grained structure as a result of isochronal annealing is accompanied by the sharp decrease of microhardness and the decrease of dislocation density. The differences in thermal stability of both alloys are related to different conditions of ECAP pressing and the phase stability, namely the presence of stable Al2Ca precipitates in AX41 alloy. Microscopic mechanisms controlling the structure stability of both alloys are discussed.