Microstructure and mechanical behavior of nanocrystalline metals

Agnew, Sean R.; Elliott, B. R.; Youngdahl, Carl J.; Hemker, Kevin J.; Weertman, J.

doi:10.1016/s0921-5093(00)00669-9

Cited by 95 publications

(38 citation statements)

References 20 publications

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“…In addition to softening, a substantial increase (50% or less) in hardness has been reported after annealing some nanocrystalline materials; this has often been attributed to recrystallization of amorphous phases and/or grain boundary relaxation. Figure 8 5,36,[120][121][122][123][124][125][126][127][128][129][130][131][132] plots a number of mechanical properties (hardness, compression, and tension tests) as a function of the inverse grain size (i.e., Hall-Petch relationship, Eq. 1).…”

Section: Yield Stress and Hardnessmentioning

confidence: 99%

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“Bulk” Nanocrystalline Metals: Review of the Current State of the Art and Future Opportunities for Copper and Copper Alloys

Tschopp

Murdoch

Kecskes

et al. 2014

JOM

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It is a new beginning for innovative fundamental and applied science in nanocrystalline materials. Many of the processing and consolidation challenges that have haunted nanocrystalline materials are now more fully understood, opening the doors for bulk nanocrystalline materials and parts to be produced. While challenges remain, recent advances in experimental, computational, and theoretical capability have allowed for bulk specimens that have heretofore been pursued only on a limited basis. This article discusses the methodology for synthesis and consolidation of bulk nanocrystalline materials using mechanical alloying, the alloy development and synthesis process for stabilizing these materials at elevated temperatures, and the physical and mechanical properties of nanocrystalline materials with a focus throughout on nanocrystalline copper and a nanocrystalline Cu-Ta system, consolidated via equal channel angular extrusion, with properties rivaling that of nanocrystalline pure Ta. Moreover, modeling and simulation approaches as well as experimental results for grain growth, grain boundary processes, and deformation mechanisms in nanocrystalline copper are briefly reviewed and discussed. Integrating experiments and computational materials science for synthesizing bulk nanocrystalline materials can bring about the next generation of ultrahigh strength materials for defense and energy applications.

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Section: Yield Stress and Hardnessmentioning

confidence: 99%

“…8. Hardness and yield strength (compression and tension) as a function of grain size for multiple nanocrystalline copper references from the literature (hardness, 36,120-124 compression, 121,123,[125][126][127][128] and tension 5,121,122,125,[128][129][130][131][132] ). Fig.…”

Section: Ductilitymentioning

confidence: 99%

“Bulk” Nanocrystalline Metals: Review of the Current State of the Art and Future Opportunities for Copper and Copper Alloys

Tschopp

Murdoch

Kecskes

et al. 2014

JOM

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“…The advent of nanocrystalline (NC) metals, [2] with their superior strength and hardness to conventional coarse-grained (CG) counterparts, offers the possibility of a new metallurgical pathway to improved fatigue performance. [3][4][5][6][7][8][9] Indeed, published literature on the fatigue performance of NC metals clearly demonstrates improvements in fatigue strength over CG metals. [10][11][12][13][14][15] Aside from quantitative improvements in fatigue performance, NC metals also hold the possibility of new insight into the mechanisms responsible for traditional fatigue failure.…”

Section: Introductionmentioning

confidence: 99%

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Boyce

Padilla

2011

Metall Mater Trans A

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Fatigue failure due to repetitive loading of metallic devices is a pervasive engineering concern. The present work reveals extraordinary fatigue resistance in nanocrystalline (NC) alloys, which appears to be associated with the small (<100 nm) grain size inhibiting traditional cyclic damage processes. In this study, we examine the fatigue performance of three electrodeposited NC Nibased metals: Ni, Ni-0.5Mn, and Ni-22Fe (PERMALLOY). When subjected to fatigue stresses at and above the tensile yield strength where conventional coarse-grained (CG) counterparts undergo low-cycle fatigue failure (<10 4 cycles to failure), these alloys exhibit exceptional fatigue lives (in some cases, >10 7 cycles to failure). Postmortem examinations show that failed samples contain an aggregate of coarsened grains at the crack initiation site. The experimental data and accompanying microscopy suggest that the NC matrix undergoes abnormal grain growth during cyclic loading, allowing dislocation activity to persist over length scales necessary to initiate a fatigue crack by traditional fatigue mechanisms. Thus, the present observations demonstrate anomalous fatigue behavior in two regards: (1) quantitatively anomalous when considering the extremely high stress levels needed to drive fatigue failure and (2) mechanistically anomalous in light of the grain growth process that appears to be a necessary precursor to crack initiation.

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“…[2][3][4] While nanostructured materials synthesized by the consolidation of nanopowders often exhibit brittle behavior, especially under tensile loading, 1,5 those produced by severe plastic deformation (SPD) techniques often have both high strength and good ductility. [6][7][8][9][10] SPD techniques refine grains by introducing large plastic strains into a coarsegrained material, typically a metal or alloy.…”

Section: Introductionmentioning

confidence: 99%

Nanostructures in Ti processed by severe plastic deformation

et al. 2003

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Metals and alloys processed by severe plastic deformation (SPD) can demonstrate superior mechanical properties, which are rendered by their unique defect structures. In this investigation, transmission electron microscopy and x-ray analysis were used to systematically study the defect structures, including grain and subgrain structures, dislocation cells, dislocation distributions, grain boundaries, and the hierarchy of these structural features, in nanostructured Ti produced by a two-step SPD procedure-warm equal channel angular pressing followed by cold rolling. The effects of these defect structures on the mechanical behaviors of nanostructured Ti are discussed.

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Microstructure and mechanical behavior of nanocrystalline metals

Cited by 95 publications

References 20 publications

“Bulk” Nanocrystalline Metals: Review of the Current State of the Art and Future Opportunities for Copper and Copper Alloys

“Bulk” Nanocrystalline Metals: Review of the Current State of the Art and Future Opportunities for Copper and Copper Alloys

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Nanostructures in Ti processed by severe plastic deformation

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