In Situ TEM Tensile Testing of Bicrystals with Tailored Misorientation Angles
In Situ TEM Tensile Testing of Bicrystals with Tailored Misorientation Angles
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DOI：
10.1016/j.actamat.2021.117505
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发表时间：
2021-11
期刊：
影响因子：
9.4
通讯作者：
M. Kiani;Lucia T. Gan;R. Traylor;Rui Yang;C. Barr;K. Hattar;Jonathan A. Fan;X. Wendy Gu
中科院分区：
文献类型：
--
作者：
M. Kiani;Lucia T. Gan;R. Traylor;Rui Yang;C. Barr;K. Hattar;Jonathan A. Fan;X. Wendy Gu
晶界具有复杂的结构特征，影响金属和合金的强度、延展性和断裂。晶界取向差角已被确定为控制其力学行为的关键参数，但取向差角的影响在多晶材料中一直具有挑战性。在这里，我们描述了使用的双晶Au薄膜使用快速熔体生长过程中，研究在一个单一的晶界变形。拉伸测试是在具有不同取向差角的双晶体上进行的，使用原位TEM，以及在单晶样品上。塑性变形是通过自由表面的位错成核而开始的。没有观察到晶界滑动，并且在所有情况下，通过塑性塌陷远离晶界发生失效。在这些纳米双晶体的故障行为似乎不依赖于取向差角或晶界能，而是有一个更复杂的依赖于样品的表面结构和位错活动。
Grain boundaries have complex structural features that influence strength, ductility and fracture in metals and alloys. Grain boundary misorientation angle has been identified as a key parameter that controls their mechanical behavior, but the effect of misorientation angle has been challenging to isolate in polycrystalline materials. Here, we describe the use of bicrystal Au thin films made using a rapid melt growth process to study deformation at a single grain boundary. Tensile testing is performed on bicrystals with different misorientation angles usingin situTEM, as well as on a single crystalline sample. Plastic deformation is initiated through dislocation nucleation from free surfaces. Grain boundary sliding is not observed, and failure occurs away from the grain boundary through plastic collapse in all cases. The failure behavior in these nanoscale bicrystals does not appear to depend on the misorientation angle or grain boundary energy but instead has a more complex dependence on sample surface structure and dislocation activity.