Strain-hardening behavior and microstructure development in polycrystalline as-cast Mg-Zn-Y alloys with LPSO phase subjected to cyclic loading
Strain-hardening behavior and microstructure development in polycrystalline as-cast Mg-Zn-Y alloys with LPSO phase subjected to cyclic loading
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DOI：
10.1016/j.msea.2016.06.069
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发表时间：
2016-08
期刊：
影响因子：
6.4
通讯作者：
Kazuma Shiraishi;T. Mayama;M. Yamasaki;Y. Kawamura
中科院分区：
文献类型：
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作者：
Kazuma Shiraishi;T. Mayama;M. Yamasaki;Y. Kawamura
研究了不同长周期堆积有序相体积分数的Mg-Zn-Y合金在循环载荷作用下的应变硬化行为和显微组织变化。对于所有的合金，在0.5%的恒定应变幅下循环加载试验，最多100次循环，显示出不对称的循环硬化行为。也就是说，在循环加载过程中，压缩峰值应力的绝对值显著增加，而拉伸峰值应力略有下降。随着LPSO相体积分数的增加，应力幅值显著增加。循环加载试验后，压缩预加载高达200或250 MPa的应力幅值显着增加，而一些扭结带开发过程中预加载。对于循环硬化行为，随动硬化的增加的贡献是显着的，在具有较高的体积分数的LPSO相的合金。透射电镜观察表明，Mg 85 Zn 6 Y 9合金在循环变形过程中形成了一个形变诱导带，在该带中，溶质元素从18 R-LPSO转变为hcp-Mg。
The strain-hardening behavior and microstructural development of polycrystalline as-cast Mg-Zn-Y alloys with various volume fractions of the long-period stacking ordered (LPSO) phase subjected to cyclic loading were experimentally evaluated. For all alloys, cyclic loading tests with a constant strain amplitude of 0.5% for up to 100 cycles showed asymmetric cyclic hardening behavior. That is, the absolute value of the compressive peak stress significantly increased during cyclic loading while the tensile peak stress slightly decreased. With increasing volume fraction of the LPSO phase, the stress amplitude significantly increased. Cyclic loading tests after compressive preloading up to 200 or 250 MPa resulted in a significant increase in the stress amplitude, while a number of kink bands developed during preloading. For the cyclic hardening behavior, the contribution of the increase in kinematic hardening was significant in the alloys with a higher volume fraction of the LPSO phase. Transmission electron microscopy observation of the cyclically deformed Mg85Zn6Y9alloy indicated the formation of a deformation-induced band, where the crystal structure was transformed from 18R-LPSO to hcp-Mg with the exclusion of solute elements.