Strong Strain Hardening in Nanocrystalline Nickel
Strong Strain Hardening in Nanocrystalline Nickel
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DOI：
10.1103/physrevlett.103.205504
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发表时间：
2009-11-13
影响因子：
8.6
通讯作者：
Wei, Q.
中科院分区：
文献类型：
--
作者：
Wu, X. L.;Zhu, Y. T.;Wei, Q.
低应变硬化迄今为止被认为是大多数纳米晶（NC）金属的固有行为，由于它们不能积累位错。在这封信中，我们表现出强大的应变硬化NC镍与晶粒尺寸类似的20纳米下大的塑性应变。与通常的看法相反，我们已经观察到显着的位错积累在晶粒内部。这主要是通过Lomer-Cottrell锁实现的，其钉扎形成锁的位错并阻碍位错运动。这些观察结果可能有助于开发强度和韧性NC金属和合金。
Low strain hardening has hitherto been considered an intrinsic behavior for most nanocrystalline (NC) metals, due to their perceived inability to accumulate dislocations. In this Letter, we show strong strain hardening in NC nickel with a grain size of similar to 20 nm under large plastic strains. Contrary to common belief, we have observed significant dislocation accumulation in the grain interior. This is enabled primarily by Lomer-Cottrell locks, which pin the lock-forming dislocations and obstruct dislocation motion. These observations may help with developing strong and ductile NC metals and alloys.