材料科学
软化
晶界
铜
粒度
打滑(空气动力学)
微晶
硬化(计算)
复合材料
晶界强化
位错
冶金
极限抗拉强度
晶体孪晶
微观结构
热力学
物理
图层(电子)
作者
Lei Lü,X. Chen,Xiaoxu Huang,K. Lu
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2009-01-30
卷期号:323 (5914): 607-610
被引量:1684
标识
DOI:10.1126/science.1167641
摘要
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced strain hardening and tensile ductility. The strongest twin thickness originates from a transition in the yielding mechanism from the slip transfer across twin boundaries to the activity of preexisting easy dislocation sources.
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