The low-cycle fatigue behavior of solutionized (T4) and aged (T6) WE43 magnesium alloys was studied at room temperature. The total strain amplitudes (Δε_t/2) were 0.4%, 0.5%, 0.6%, 0.7% and 1.0%. Detailed microstructure evolution was characterized by scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The results showed that plastic strain amplitude decreased with the increasing cycle number in T4 alloy, which is due to the dense persistent slip bands (PSBs) and dynamic precipitates hindering <a> dislocation slip. In contrast, the plastic strain amplitude increases gradually in T6 alloy, which is attributed to the enhanced activation of pyramidal slip. The low-cycle fatigue life of T6 alloy with larger fatigue ductility coefficient is longer than that of T4 alloy. The Coffin-Manson model can accurately predict the fatigue life of T4 and T6 alloys compared to Jahed-Varvani (JV) energy model. For T4 alloy, the fatigue damage mechanism was dominated by basal slip. For T6 alloy, the enhanced pyramidal slip plays an important role to accommodate plastic deformation.

3% Y₂O_3p/ZGK200 composites were subjected to unidirectional rolling (UR) and cross rolling (CR) at 400 ℃ and 350 ℃ followed by annealing at 300 ℃ for 1 h. The microstructure, texture and mechanical properties of rolled and annealed composites were systematically studied. The rolled composites exhibited a heterogeneous microstructure, consisting of deformed grains elongated along rolling direction (RD) and Y₂O₃ particles bands distributed along RD. After annealing, static recrystallization (SRX) occurred and most deformed grains transformed into equiaxed grains. A non-basal texture with two strong T-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR, indicating that rolling path had great influences on texture of the composites. After annealing process, R-texture component disappeared or weakened, as results, a non-basal texture with double peaks tilting from normal direction (ND) to transverse direction (TD) and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites, respectively. The yield strength of rolled composites after UR showed obvious anisotropy along RD and TD while a low anisotropic yield strength was obtained after CR. Some Y₂O₃ particles broke during rolling. The fracture of the composites was attributed to the existence of Y₂O₃ clusters and interfacial debonding between particles and matrix during tension, as a result, the ductility was not as superior as matrix alloy.