Dislocations with edge components in nanocrystalline bcc Mo

Cheng, Guangming; Xu, Weizong; Jian, Weiwei; Yuan, Hao; Tsai, Ming–Hung; Zhu, Yuntian; Zhang, Yongfeng; Millett, Paul C.

doi:10.1557/jmr.2012.403

Cited by 33 publications

(17 citation statements)

References 41 publications

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“…During severe plastic deformation, forest dislocations and a high density of grain boundaries are formed. From recent studies on nanocrystalline bcc-metals with grain sizes smaller 300 nm, it is known that the deformation is mainly governed by edge dislocations [23][24], and the thermally activated contribu-200 tion of screw dislocations is completely omitted for grain 230 230 sizes below 100 nm. This might further affect the time dependent deformation behavior.…”

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confidence: 99%

Thermally activated deformation processes in body-centered cubic Cr – How microstructure influences strain-rate sensitivity

et al. 2015

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confidence: 99%

Thermally activated deformation processes in body-centered cubic Cr – How microstructure influences strain-rate sensitivity

et al. 2015

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“…[1,2] For example, deformation twinning has been frequently observed even in NC face-centered cubic (fcc) materials that do not deform by twinning in their coarse-grained counterparts. [2,3] Formation of twins in NC metals [2,4,5] plays a critical role in their physical and mechanical properties, such as good electrical conductivity, and excellent resistance to currentinduced diffusion.…”

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confidence: 99%

Macroscopic Twinning Strain in Nanocrystalline Cu

Zhu

Narayan

2013

Materials Research Letters

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“…4b and d. The observed dislocations in NC Mo were mainly from the edge or mixed dislocations [29,42] and their density was almost at the same order of magnitude in both irradiated and unirradiated samples. But most of them in irradiated CG Mo might be from the projection of dislocation loops since no obvious dislocation line was observed via two-beam imaging.…”

Section: O M / L O C a T E / S C R I P T A M A Tmentioning

confidence: 83%

“…Refining the grains of materials into nanometer size can significantly alter the physical, chemical and mechanical behaviors of the materials [25][26][27][28][29][30][31]. Previous reports [32-35] on fcc/bcc nanolayered composites have showed extreme tolerance to He bubbles, which are prone to segregate at interphase boundaries.…”

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confidence: 99%

Grain size effect on radiation tolerance of nanocrystalline Mo

Cheng

Wang

et al. 2016

Scripta Materialia

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We report a significant grain size effect on radiation tolerance of nanocrystalline Mo under He ion irradiation. Irradiation-induced dislocation loops mainly contribute to the irradiation-induced hardening of Mo films with grain size of N90 nm, while few such loops in those with grain size of b90 nm. The hardness increment after irradiation decreases with decreasing the grain size, and approaches zero at the grain size of 25 nm. Also, the size and the density of irradiation-induced He bubbles decrease as the grain size decreases. This observation provides direct evidence that nanocrystalline body-centered-cubic metals have greater radiation tolerance than their ultra-fine-grained or coarse-grained counterparts.Published by Elsevier Ltd. Keywords:Radiation damage Body-centered cubic (bcc) Nanocrystalline Grain size effect Magnetron sputtering Radiation damage is one of the critical issues for developing advanced materials used in next generation nuclear plants [1-8] and spacecrafts [9]. Hardening, swelling, embrittlement and creep are some of the critical issues associated with radiation damage. Irradiation can induce interstitials, vacancies or He bubbles in microstructure, which will further agglomerate to form loops, interstitial or vacancy clusters and voids in materials [10,11]. Formation of voids will lead to swelling and embrittlement, which are the main cause of material failure under irradiation environment [12]. Therefore, how to control the generation of irradiation-induced defects and mitigate the negative effects of He bubbles is the key to design advanced radiation tolerant materials with a balance of mechanical and thermal properties [2,13].Body-centered cubic (bcc) metals and alloys have attracted much attention in the past decade due to their reduced-activation under irradiation environment [14][15][16][17][18]. The studies on the oxide-dispersion strengthened (ODS) ferrite steels [19][20][21][22] have showed great radiation tolerance since dispersed nanoparticles in the matrix increase the volume fraction of the interfaces which can act as sinks for irradiation-induced defects, especially for He bubbles.Similarly, nanocrystalline (NC) materials exhibit great potential for such applications because a large fraction of grain and interphase boundaries can act as effective sinks for irradiation-induced vacancies and bubbles [2,6,23,24]. Refining the grains of materials into nanometer size can significantly alter the physical, chemical and mechanical behaviors of the materials [25][26][27][28][29][30][31]. Previous reports [32-35] on fcc/bcc nanolayered composites have showed extreme tolerance to He bubbles, which are prone to segregate at interphase boundaries. Bulk NC metals have also displayed extraordinary radiation healing behavior due to grain boundary (GB) accommodation of defects [36][37][38].Although there are many reports about the radiation damage on NC metals and alloys, it remains elusive about how the change of grain size affects the radiation tolerance. To explore this issue, here we in...

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Dislocations with edge components in nanocrystalline bcc Mo

Cited by 33 publications

References 41 publications

Thermally activated deformation processes in body-centered cubic Cr – How microstructure influences strain-rate sensitivity

Thermally activated deformation processes in body-centered cubic Cr – How microstructure influences strain-rate sensitivity

Macroscopic Twinning Strain in Nanocrystalline Cu

Grain size effect on radiation tolerance of nanocrystalline Mo

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