He Chao, Wu Yujuan, Peng Liming, Su Ning, Li Xue, Yang Kun, Liu Yongjie, Yuan Shucheng, Tian Renhui
School of Architecture and Civil Engineering, Chengdu University, Chengdu 610105, China.
Key Laboratory of Deep Earth Science and Engineering, Ministry of Education, Sichuan University, Chengdu 610065, China.
Materials (Basel). 2018 Nov 30;11(12):2429. doi: 10.3390/ma11122429.
Cyclic deformation at low-stress amplitudes of a rare earth-containing magnesium alloy (Mg⁻Gd⁻Y⁻Zr) was investigated with emphasis on the responsible microstructural relationship between deformation mechanism and fatigue crack initiation. The results show that the microstructural deformation is extremely inhomogeneous at the low-stress amplitudes. Both deformation twinning and non-basal slip are barely observed, and basal slip is the predominant deformation to accommodate micro-plasticity. Fatigue crack initiation occurred at the basal slip bands, causing the morphology of facet on the fracture surface. Therefore, the basal slip is of prime importance in low-stress cyclic deformation and fatigue failure, and fatigue improvement could potentially be obtained through hindering the motion of basal dislocation by microstructural obstacles.
研究了一种含稀土镁合金（Mg-Gd-Y-Zr）在低应力幅值下的循环变形，重点关注变形机制与疲劳裂纹萌生之间的微观结构关系。结果表明，在低应力幅值下，微观结构变形极不均匀。几乎未观察到变形孪生和非基面滑移，基面滑移是适应微观塑性的主要变形方式。疲劳裂纹萌生于基面滑移带，导致断口表面出现小平面形貌。因此，基面滑移在低应力循环变形和疲劳失效中至关重要，通过微观结构障碍阻碍基面位错运动可能实现疲劳性能的改善。
