Twinning effects on strength and plasticity of metallic materials

Wang, Jian; Zhang, Xinghang

doi:10.1557/mrs.2016.67

Cited by 96 publications

(32 citation statements)

References 93 publications

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“…[26][27][28] Interestingly, when the NT structures are introduced into the crystalline metals, which means that a high density of twin boundaries (TBs) is embedded in the grains, this kind of special nanostructure can act as coherent boundaries to improve the mechanical and physical properties of metals. 14,24,25,[35][36][37][38][39][40][41][42][43][44] The unique mechanical properties of NT materials derive from dislocation-TBs interactions which are different from dislocation-GBs and dislocation-dislocation interactions. Owing to the complicated dislocation-TBs reactions, NT materials breakthrough the conventional dilemma of strength and ductility, realizing significant strengthening and good ductility.…”

Section: Introductionmentioning

confidence: 99%

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

Sun

2018

npj Comput Mater

134

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The recent studies on nanotwinned (NT) and hierarchical nanotwinned (HNT) face-centered cubic (FCC) metals are presented in this review. The HNT structures have been supposed as a kind of novel structure to bring about higher strength/ductility than NT counterparts in crystalline materials. We primarily focus on the recent developments of the experimental, atomistic and theoretical studies on the NT and HNT structures in the metallic materials. Some advanced bottom-up and top-down techniques for the fabrication of NT and HNT structures are introduced. The deformation induced HNT structures are available by virtue of severe plastic deformation (SPD) based techniques while the synthesis of growth HNT structures is so far almost unavailable. In addition, some representative molecular dynamics (MD) studies on the NT and HNT FCC metals unveil that the nanoscale effects such as twin spacing, grain size and plastic anisotropy greatly alter the performance of NT and HNT metals. The HNT structures may initiate unique phenomena in comparison with the NT ones. Furthermore, based on the phenomena and mechanisms revealed by experimental and MD simulation observations, a series of theoretical models have been proposed. They are effective to describe the mechanical behaviors of NT and HNT metals within the applicable scope. So far the development of manufacturing technologies of HNT structures, as well as the studies on the effects of HNT structures on the properties of metals are still in its infancy. Further exploration is required to promote the design of advanced materials.

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Section: Introductionmentioning

confidence: 99%

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

Sun

2018

npj Comput Mater

134

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“…Highly textured and nanotwinned Cu interconnects are desirable for these applications as they may help reduce stresses caused by thermal fluctuations in 3D integrated circuits, increase their reliability, and electromigration resistance [4–7]. PED has been shown to enable more control over the deposition process than conventional direct circuit (DC) electroplating due to the tunable on- and off-times of the current pulse waves.…”

Section: Introductionmentioning

confidence: 99%

“…Twin boundaries differ from grain boundaries since they do not adversely impact electron-mobility, yet they still hinder dislocation movement similar to that of high angle grain boundaries [5,25]. The spacing of these nanotwins has also been shown to dictate the strength of the material [5,7,24] and can be tuned with PCD [20,22]. PED is capable of producing nanotwins more readily than direct current ECD [20].…”

Section: Introductionmentioning

confidence: 99%

The influence of pulse plating frequency and duty cycle on the microstructure and stress state of electroplated copper films

et al. 2017

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In this work we studied the impact of pulse electroplating parameters on the cross-sectional and surface microstructures of blanket copper films using electron backscattering diffraction and x-ray diffraction. The films evaluated were highly (111) textured in the direction perpendicular to the film surface. The degree of preferential orientation was found to decrease with longer pulse on-times, due to strain energy driven growth of other grain orientations. Residual biaxial stresses were also measured in the films and higher pulse frequencies during deposition led to smaller biaxial stresses in the films. Film stress was also found to correlate with the amount of twinning in the copper film cross-sections. This has been attributed to the twins’ thermal stability and mechanical properties.

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“…It is important to emphasize that CTBs are not always perfect. Short segments of incoherent Σ3{112} TBs (ITBs) are routinely observed in electrodeposited and sputtered nanotwinned Cu and Ag metals by transmission electron microscopy (TEM) [2,37]. Even if ITBs are not detectable by standard TEM, a recent study by Wang et al [38] using sub-nm-scale inverse pole figure orientation mapping on magnetronsputtered nanotwinned Cu, has identified the existence of intrinsic kink-like defects on CTBs of ~ 1-5 nm in height.…”

Section: Introductionmentioning

confidence: 99%

Influence of intrinsic kink-like defects on screw dislocation – coherent twin boundary interactions in copper

Fang

Sansoz

2017

Acta Materialia

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The interaction mechanisms between a dislocation and a twin boundary in nanotwinned face-centered cubic metals are well understood in terms of perfect coherent interfaces. Processes involving intrinsic incoherent twin boundary defects, however, remain largely unexplored, despite recent evidence suggesting that imperfect twin boundaries containing short kink-like step defects contribute notably to plastic deformation and twin stability in large nanotwinned grains. Here, molecular dynamics simulation is used to study the underlying interaction of screw dislocations with either 0° or 60° atomic-scale kink twin boundary defects, in order to understand how the presence of imperfect twin boundaries can alter hardening and ductility mechanisms in nanotwinned copper. It is found that kinked twin boundaries are effective in changing the mechanisms from direct dislocation transmission to dislocation absorption when the applied shear strain exceeds 1.06%, with pronounced hardening arising from such transformation. Hardening by dislocation pinning from individual kink steps is also manifest for 60° intersections. On the contrary, twin boundary defects produce no hardening at low applied strains when dislocation absorption at the twin boundary is already prevailing.

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Twinning effects on strength and plasticity of metallic materials

Abstract: Abstract

Cited by 96 publications

References 93 publications

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

The influence of pulse plating frequency and duty cycle on the microstructure and stress state of electroplated copper films

Influence of intrinsic kink-like defects on screw dislocation – coherent twin boundary interactions in copper

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