Direct imaging of short-range order and its impact on deformation in Ti-6Al

Chemical short-range order (SRO) within a nominally single-phase solid solution is known to affect the mechanical properties of alloys. While SRO has been indirectly related to deformation, direct observation of the SRO domain structure, and its effects on deformation mechanisms at the nanoscale, has remained elusive. Here, we report the direct observation of SRO in relation to deformation using energy-filtered imaging in a transmission electron microscope (TEM). The diffraction contrast is enhanced by reducing the inelastically scattered electrons, revealing subnanometer SRO-enhanced domains. The destruction of these domains by dislocation planar slip is observed after ex situ and in situ TEM mechanical testing. These results confirm the impact of SRO in Ti-Al alloys on the scale of angstroms. The direct confirmation of SRO in relationship to dislocation plasticity in metals can provide insight into how the mechanical behavior of concentrated solid solutions by the material’s thermal history.

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Ordering process of Cu 3 Pt from short-range order state studied by in-situ TEM observation

Micron ◽

10.1016/s0968-4328(99)00135-3 ◽

2000 ◽

Vol 31 (5) ◽

pp. 539-542

Author(s):

N Chiwata ◽

T Sakai ◽

A Matsumoto ◽

N Kuwano ◽

K Oki

Keyword(s):

Short Range ◽

Short Range Order ◽

Range Order ◽

In Situ Tem ◽

Order State

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In situ TEM observation of long range ordering via short range order in Cu3Pt

Bulletin of Materials Science ◽

10.1007/bf02749988 ◽

1999 ◽

Vol 22 (3) ◽

pp. 697-700 ◽

Cited By ~ 1

Author(s):

N Kuwano ◽

N Chiwata ◽

K Oki

Keyword(s):

Long Range ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

In Situ Tem ◽

Long Range Ordering

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A transmission electron microscopy study of the effect of quenched-in vacancies on long and short-range order in Cu3Au alloy

Philosophical Magazine ◽

10.1080/14786437008238451 ◽

1970 ◽

Vol 21 (172) ◽

pp. 649-657 ◽

Cited By ~ 3

Author(s):

A. Camanzi

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Short Range ◽

Short Range Order ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Range Order ◽

Transmission Electron Microscopy Study ◽

Transmission Electron ◽

Cu3au Alloy

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In-situ TEM studies on stick-slip friction characters of sp2 nanocrystallited carbon films

Friction ◽

10.1007/s40544-021-0551-z ◽

2022 ◽

Author(s):

Xue Fan ◽

Zelong Hu ◽

Wenchao Huang

Keyword(s):

Shear Stress ◽

Shear Strength ◽

Interfacial Adhesion ◽

Carbon Films ◽

Ex Situ ◽

In Situ Tem ◽

Stick Slip ◽

Slip Step ◽

Transmission Electron

AbstractCarbon films with two different kinds of sp2 nanocrystallited structure were investigated to study the stick-slip friction with the in-situ and ex-situ tests. In-situ transmission electron microscope (TEM) observation and nanofriction tests revealed that the origins of stick and slip varied with shear stress and film deformation. At the stick stage, shear stress gradually increased with the contact strengthened until reached the shear strength to break the interfacial adhesion; at the slip stage, the shear stress decreased and accompanied with film deformation. During the sliding process, adhesive deformation resulted in the large stick-slip step while ploughing deformation led to a smoother step. Ex-situ nanofriction tests on a series of sp2 nanocrystallited carbon films with different irradiation energies showed the expected sliding behavior with the in-situ results. This study first clarified the mechanism of stick-slip friction with the in-situ TEM observation, which plays the important role for the micro and nano application of sp2 nanocrystallited carbon films.

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Magnetically driven short-range order can explain anomalous measurements in CrCoNi

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2020540118 ◽

2021 ◽

Vol 118 (13) ◽

pp. e2020540118

Author(s):

Flynn Walsh ◽

Mark Asta ◽

Robert O. Ritchie

Keyword(s):

First Principles ◽

Short Range ◽

Short Range Order ◽

Nearest Neighbor ◽

Range Order ◽

Magnetic Interactions ◽

First Principles Calculations ◽

Principal Element ◽

The Impact ◽

Magnetically Aligned

The presence, nature, and impact of chemical short-range order in the multi-principal element alloy CrCoNi are all topics of current interest and debate. First-principles calculations reveal that its origins are fundamentally magnetic, involving repulsion between like-spin Co–Cr and Cr–Cr pairs that is complemented by the formation of a magnetically aligned sublattice of second-nearest-neighbor Cr atoms. Ordering models following these principles are found to predict otherwise anomalous experimental measurements concerning both magnetization and atomic volumes across a range of compositions. In addition to demonstrating the impact of magnetic interactions and resulting chemical rearrangement, the possible explanation of experiments would imply that short-range order of this type is far more prevalent than previously realized.

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Short-range order in amorphous co-sputtered Ta-Al thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145649 ◽

1986 ◽

Vol 44 ◽

pp. 860-861

Author(s):

J.C. Barry ◽

R.S. Timsit ◽

D. Landheer

Keyword(s):

Thin Film ◽

Thin Films ◽

Electron Microscope ◽

High Resolution ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Transmission Electron ◽

Thin Film Resistors ◽

Diffraction Patterns

Tantalum-aluminium thin films have assumed considerable technological importance since the discovery in the late 1960's that the films are useful in the fabrication of thin film resistors and capacitors. It is generally claimed that these films, when prepared by co-sputtering Ta and Al, are amorphous over a range of Ta concentrations extending approximately from 15 to 75 at%, and are crystalline beyond this range. Diffuse electron diffraction patterns and ‘mottle pattern’ transmission electron micrographs are typical characteristics of the amorphous phase. In this present study we have attempted to identify any atomic short range order in the amorphous Ta-Al films and to follow the changes in this order as the Ta concentration increases across the amorphous/crystalline transition. The co-sputtered Ta-Al films of ≈100A thickness were examined in a high resolution 4000EX electron microscope (top entry, ±15°(x,y) tilt, Cs = 1.0mm ) at 400kV.

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Reciprocal space mapping of silver nanoparticle array re-assembly and oxidation

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314092547 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C745-C745

Author(s):

Matej Jergel ◽

Peter Siffalovic ◽

Karol Vegso ◽

Monika Benkovicova ◽

Andrej Vojtko ◽

...

Keyword(s):

Metal Oxide ◽

Silver Nanoparticle ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Ex Situ ◽

Stage Iii ◽

Self Assembled ◽

Uv Ozone ◽

Surfactant Removal

Self-assembled metal oxide nanoparticle layers have attracted much attention recently due to potential applications in sensors. Here we report on a UV/ozone-driven re-assembly and oxidation of a self-assembled silver nanoparticle bilayer deposited by a modified Langmuir-Schaefer technique that was probed in-situ by simultaneous measurements of the small- and wide-angle X-ray scattering at grazing incidence (GISAXS, GIWAXS). The experiments were performed at BL23A endstation of NSRRC, Taiwan. Four distinct stages of the system response to the UV/ozone treatment were identified. In the first stage 0-120 s, a gradual extinction of Bragg rods and the nanoparticle short-range order due to a gradual surfactant removal is observed in GISAXS that is connected with an array densification and order improvement obeying the paracrystal model in the shrinking self-assembled regions. In the second stage 120-360 s, the original self-assembly goes to a total extinction while the integral intensity of Ag 111 diffraction in GIWAXS starts to decrease, suggesting the total surfactant removal. No nanoparticle short-range order is observed in stage III 360-730 s where AgO monoclinic phase due to the nanoparticle surface oxidation appears and pure Ag phase disappears. The initial AgO unit cell volume corresponding to the unstrained phase gradually expands by 4.6 % to the end of stage III. In stage IV 730-2000 s (end of measurements), new Bragg rods appear in GISAXS, suggesting a nanoparticle agglomeration with a typical correlation length of approximately 240 nm that was confirmed by ex-situ atomic force microscopy. The agglomeration does not reach saturation even after 2000 s while the AgO phase remains stable. These results have direct implications for tailored preparation of advanced sensors based on metal oxide nanoparticles. The work was supported by the projects APVV-0308-11, VEGA 2/0041/11, SAS-NSC JRP 2011/05, SAS-TUBITAK JRP 2013/6, COST MP1203 and COST CM1101.

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