Dislocation-mediated relaxation in nanograined columnar palladium films revealed by on-chip time-resolved HRTEM testing.
Dislocation-mediated relaxation in nanograined columnar palladium films revealed by on-chip time-resolved HRTEM testing.
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DOI：
10.1038/ncomms6922
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发表时间：
2015-01-05
影响因子：
16.6
通讯作者：
Pardoen, T.
中科院分区：
文献类型：
--
作者：
Colla, M. -S.;Amin-Ahmadi, B.;Idrissi, H.;Malet, L.;Godet, S.;Raskin, J. -P.;Schryvers, D.;Pardoen, T.
在最近的文献中所展示的纳米结构金属材料的高速率敏感性与大密度的内部界面所支持的热激活变形机制的优势有关。在这里，我们报告的时间分辨高分辨率电子透射显微镜蠕变测试薄纳米晶粒薄膜使用芯片上的纳米力学测试。对钯进行测试，钯在室温下表现出出乎意料的大蠕变速率。尽管小的30纳米的晶粒尺寸，弛豫被认为是介导的位错机制。位错与晶粒中存在的生长纳米孪晶相互作用，导致孪晶边界的相干性丧失。存储位错的密度首先随着施加的变形而增加，然后随着时间而减小以驱动额外的变形，而没有观察到晶界机制。这种快速弛豫构成了开发各种微米和纳米技术（例如用于氢气应用的钯膜）的关键问题。 纳米结构的金属材料涉及通常由晶界相关机制引起的高速率敏感性。在这里，作者报告的力学测试独立的钯薄膜，并表明，蠕变与位错，而不是晶界。
The high-rate sensitivity of nanostructured metallic materials demonstrated in the recent literature is related to the predominance of thermally activated deformation mechanisms favoured by a large density of internal interfaces. Here we report time-resolved high-resolution electron transmission microscopy creep tests on thin nanograined films using on-chip nanomechanical testing. Tests are performed on palladium, which exhibited unexpectedly large creep rates at room temperature. Despite the small 30-nm grain size, relaxation is found to be mediated by dislocation mechanisms. The dislocations interact with the growth nanotwins present in the grains, leading to a loss of coherency of twin boundaries. The density of stored dislocations first increases with applied deformation, and then decreases with time to drive additional deformation while no grain boundary mechanism is observed. This fast relaxation constitutes a key issue in the development of various micro- and nanotechnologies such as palladium membranes for hydrogen applications. Nanostructured metallic materials involve a high rate sensitivity usually resulting from grain boundary related mechanisms. Here, the authors report mechanical tests on freestanding Pd thin films and show that creep is associated with dislocations rather than grain boundaries.
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DOI：
10.1007/bf02666659
发表时间：
1989-11-01
期刊：
METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
影响因子：
--
作者：
NIX, WD
通讯作者：
NIX, WD
影响因子：
4.6
作者：
Lee, Joon Hwan;Holland, Troy B.;Mukherjee, Amiya K.;Zhang, Xinghang;Wang, Haiyan
通讯作者：
Wang, Haiyan
影响因子：
9.8
作者：
Wang, B.;Idrissi, H.;Schryvers, D.
通讯作者：
Schryvers, D.
纳米尺寸的孪晶在纯铜中引起流动应力的高速率敏感性
影响因子：
9.4
作者：
Lu, L;Schwaiger, R;Suresh, S
通讯作者：
Suresh, S
影响因子：
29.4
作者：
Idrissi, Hosni;Wang, Binjie;Pardoen, Thomas
通讯作者：
Pardoen, Thomas