Enhanced Hall-Petch strengthening in graphene/Cu nanocomposites
Enhanced Hall-Petch strengthening in graphene/Cu nanocomposites
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DOI：
10.1016/j.jmst.2021.02.013
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发表时间：
2021-03
影响因子：
10.9
通讯作者：
Shuang Zhang;Fei Wang;P. Huang
中科院分区：
文献类型：
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作者：
Shuang Zhang;Fei Wang;P. Huang
晶粒尺寸与强度的关系，即Hall-Petch关系，已被证实适用于晶体金属和合金。然而，当晶粒尺寸减小到低于临界值的纳米级时，最终会发生软化。因此，有必要找到一种方法来打破强度限制，避免从位错介导的变形机制过渡到晶界介导的过程。通过用石墨烯取代纳米晶Cu的晶界，分子动力学模拟结果表明，随着晶粒尺寸的减小，石墨烯-晶界（GrB）嵌入的GrB/Cu纳米复合材料的Hall-Petch斜率增大。GrB/Cu纳米复合材料中不存在逆Hall-Petch关系和极高的强度是由纳米复合材料的高度非均匀结构引起的高背应力和丰富的位错活动来解释的。
Grain size dependent strength, known as Hall-Petch relation, has been approved to be valid in crystalline metals and alloys. However, softening would eventually occur as grain size reduced into nanoscale that below a critical value. Hence, it is essential to find a way to break the strength limitation by avoiding the deformation mechanism transition from dislocation-mediated to grain-boundary-mediated processes. By replacing grain boundary (GB) of nanocrystalline Cu with graphene, in the present study, molecular dynamics simulations show that graphene-boundary (GrB) embedded GrB/Cu nanocomposites exhibit enhanced enlarged Hall-Petch slope with decreasing grain size. The absence of inverse-Hall-Petch relation and the extremely high strength derived at the GrB/Cu nanocomposites were interpreted by the high back stress and abundant dislocation activity that attributed from the high-degree of heterogeneous structure of the nanocomposites.