Anomalous effect of grain size on the room-temperature bendability of Mg-Gd alloy sheet
Anomalous effect of grain size on the room-temperature bendability of Mg-Gd alloy sheet
复制标题
晶粒尺寸对Mg-Gd合金板材室温弯曲性能的反常影响
DOI：
10.1016/j.msea.2021.142397
复制
发表时间：
2021-12-10
期刊：
影响因子：
6.4
通讯作者：
Pan, Fusheng
中科院分区：
文献类型：
--
作者：
He, Chao;Yuan, Ming;Pan, Fusheng
在这项工作中，晶粒尺寸对Mg-2Gd（wt. %）的合金板。利用电子背散射衍射（EBSD）和扫描电子显微镜（SEM）分析了弯曲过程中的组织和织构演变。结果表明，该合金具有反常的晶粒尺寸相关的弯曲性能。Mg-Gd合金中晶粒尺寸越大，其弯曲性能越差，这与传统镁合金（如AZ 31 B合金）有很大不同。Mg-Gd合金与传统的无稀土镁合金之间的这种相反的模式主要归因于在弯曲试验期间微裂纹形核机制的差异。Mg-Gd合金微裂纹的形核位置主要在晶界，而传统镁合金的微裂纹形核位置主要在晶内。此外，较大尺寸的初始微裂纹和更不均匀的应变分布在较粗晶粒的Mg-Gd样品导致在弯曲过程中的过早失效，并引起这种异常的晶粒尺寸依赖的弯曲性能。
In this work, grain size impacted on the bendability of the Mg-2Gd (wt. %) alloy sheets was investigated. The microstructures and textures evolution during the bending test were analyzed by the electron back-scattered diffraction (EBSD) and the scanning electron microscopy (SEM) technique. The results showed an anomalous grain size-dependent bendability in this alloy. The coarser grain size sample corresponded to a poorer bendability in the Mg-Gd alloys, which was dramatically different from the traditional Mg alloys (such as AZ31B alloys). This opposite mode between the Mg-Gd and traditional rare earth (RE) free Mg alloys was mainly attributed to the difference of microcracks nucleation mechanism during the bending test. The nucleation sites of microcracks were almost in the grain boundaries for the Mg-Gd alloys, while in the intragranular for the traditional Mg alloys. Furthermore, the larger size of initial microcracks and the more heterogeneous strain distributions in the coarser grain Mg-Gd samples led to a premature failure in the bending process and gave rise to this anomalous grain size-dependent bendability.