Effects of initial {10-12} twins on cyclic deformation and fatigue of magnesium alloy at low strain amplitudes
Effects of initial {10-12} twins on cyclic deformation and fatigue of magnesium alloy at low strain amplitudes
复制标题
初始{10-12}孪晶对低应变幅镁合金循环变形和疲劳的影响
DOI：
10.1016/j.matchar.2019.01.017
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发表时间：
2019
影响因子：
4.7
通讯作者：
Jiang Yanyao
中科院分区：
文献类型：
--
作者：
Wang Fenghua;Liu Man;Sun Jie;Feng Miaolin;Jin Li;Dong Jie;Jiang Yanyao
挤压后的双体积分数为60%的AZ31B （Mg-3Al-1Zn-0.5Mn）镁合金在应变幅值为0.23% ~ 0.45%的范围内沿挤压方向进行了完全反向的应变控制拉压。位错滑移是主要的塑性变形机制，不涉及持续的孪晶-失孪。在相同应变幅下，预孪晶合金的疲劳寿命明显低于挤压态合金。疲劳裂纹主要发生在母晶的棱柱状或棱柱状-基底滑移带上。预孪晶合金中母晶的材料体积减小加剧了疲劳损伤。未观察到双裂纹。
An extruded AZ31B (Mg-3Al-1Zn-0.5Mn) magnesium alloy with a twin volume fraction of 60% was subjected to fully reversed strain-controlled tension-compression along the extrusion direction at strain amplitudes ranging from 0.23% to 0.45%. Dislocation slips were the dominant plastic deformation mechanisms without involving persistent twinning-detwinning. At an identical strain amplitude, the fatigue life of the pre-twinned alloy was much lower than that of the as-extruded alloy. Fatigue cracks were mainly initiated on the prismatic or prismatic-basal slip bands in the parent grains. The material volume reduction of the parent grains in the pre-twinned alloy enhanced fatigue damage. Twin cracks were not observed.