scholarly journals Controlled growth of single-crystalline metal nanowires via thermomigration across a nanoscale junction

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
De-Gang Xie ◽  
Zhi-Yu Nie ◽  
Shuhei Shinzato ◽  
Yue-Qing Yang ◽  
Feng-Xian Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Morphological Changes ◽  
Back Stress ◽  
Solid Substrate ◽  
Metal Nanowires ◽  
Nanowire Growth ◽  
Single Crystalline ◽  
Czochralski Crystal Growth ◽  
Crystalline Metal

Abstract Mass transport driven by temperature gradient is commonly seen in fluids. However, here we demonstrate that when drawing a cold nano-tip off a hot solid substrate, thermomigration can be so rampant that it can be exploited for producing single-crystalline aluminum, copper, silver and tin nanowires. This demonstrates that in nanoscale objects, solids can mimic liquids in rapid morphological changes, by virtue of fast surface diffusion across short distances. During uniform growth, a thin neck-shaped ligament containing a grain boundary (GB) usually forms between the hot and the cold ends, sustaining an extremely high temperature gradient that should have driven even larger mass flux, if not counteracted by the relative sluggishness of plating into the GB and the resulting back stress. This GB-containing ligament is quite robust and can adapt to varying drawing directions and velocities, imparting good controllability to the nanowire growth in a manner akin to Czochralski crystal growth.

scholarly journals Versatile method for template-free synthesis of single crystalline metal and metal alloy nanowires

Nanoscale ◽  
2016 ◽  
Vol 8 (5) ◽  
pp. 2804-2810 ◽  
Author(s):  
John A. Scott ◽  
Daniel Totonjian ◽  
Aiden A. Martin ◽  
Toan Trong Tran ◽  
Jinghua Fang ◽  
...  
Keyword(s):  
Metal Alloy ◽  
Solution Phase ◽  
Metal Nanowires ◽  
Growth Technique ◽  
Single Crystalline ◽  
Alloy Nanowires ◽  
Template Free ◽  
Free Growth ◽  
Crystalline Metal

A versatile, template-free growth technique for single crystalline metal nanowires using gas or solution phase precursors.

scholarly journals Self-organization of mesoscopic silver wires by electrochemical deposition

2014 ◽  
Vol 5 ◽  
pp. 1285-1290 ◽  
Author(s):  
Sheng Zhong ◽  
Thomas Koch ◽  
Stefan Walheim ◽  
Harald Rösner ◽  
Eberhard Nold ◽  
...  
Keyword(s):  
Growth Direction ◽  
Self Organization ◽  
Metal Nanowires ◽  
Growth Speed ◽  
Ambient Conditions ◽  
Equilibrium Conditions ◽  
Single Crystalline ◽  
Unique System ◽  
The Wire ◽  
Crystalline Metal

Long, straight mesoscale silver wires have been fabricated from AgNO3 electrolyte via electrodeposition without the help of templates, additives, and surfactants. Although the wire growth speed is very fast due to growth under non-equilibrium conditions, the wire morphology is regular and uniform in diameter. Structural studies reveal that the wires are single-crystalline, with the [112] direction as the growth direction. A possible growth mechanism is suggested. Auger depth profile measurements show that the wires are stable against oxidation under ambient conditions. This unique system provides a convenient way for the study of self-organization in electrochemical environments as well as for the fabrication of highly-ordered, single-crystalline metal nanowires.

scholarly journals Innenrücktitelbild: Electrical Network of Single-Crystalline Metal Oxide Nanoclusters Wired by π-Molecules (Angew. Chem. 42/2014)

2014 ◽  
Vol 126 (42) ◽  
pp. 11565-11565
Author(s):  
Ryo Tsunashima ◽  
Yoshifumi Iwamoto ◽  
Yusuke Baba ◽  
Chisato Kato ◽  
Katsuya Ichihashi ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Electrical Network ◽  
Single Crystalline ◽  
Crystalline Metal

High Temperature Rupture Life of Nickel-Based Superalloy under Directional Solidification with High Temperature Gradient

2017 ◽  
Vol 898 ◽  
pp. 422-429 ◽  
Author(s):  
Wei Guo Zhang ◽  
Zhi Jie Liu ◽  
Song Ke Feng ◽  
Fu Zeng Yang ◽  
Lin Liu
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Temperature Stress ◽  
Solidification Rate ◽  
Rupture Life ◽  
Stress Rupture ◽  
High Temperature Stress ◽  
Stress Rupture Life ◽  
Nickel Based Superalloy

The stress rupture life of DZ125 nickel-based superalloy that was prepared by directional solidification process under the temperature gradient of 500 K/cm has been studied at 900°C and 235MPa. The results showed that with the increase of directional solidification rate from 50 μm/s to 800 μm/s, the primary dendrite arm spacing reduced from 94 μm to 35.8 μm and γ' precipitates reduced and more uniformed in size. The high temperature stress rupture life of as-cast sample increased firstly and then decreased and reached its maximum at the solidification rate of 500 μm/s. The dislocation configuration of sample with refine dendritic structure after stress rupture was investigated and discovered that the dislocations in different parts of sample had different morphology and density, which indicated that the deformation of as-cast samples were uneven during high temperature stress rupture. A lot of dislocations intertwined around carbides and at the interface of γ/γ', and the dislocation networks were destroyed and the dislocations entered γ' precipitate by the way of cutting.

Estimation of Back Stress Produced by Dislocation Interaction in Icosahedral Al-Pd-Mn

2000 ◽  
Vol 643 ◽  
Author(s):  
Hisatoshi Hirai ◽  
Akira Kitahara ◽  
Fuyuki Yoshida ◽  
Hideharu Nakashima
Keyword(s):  
Shear Stress ◽  
High Temperature ◽  
Main Part ◽  
Unit Length ◽  
Back Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Dislocation Interaction ◽  
Burgers Vector ◽  
Phonon Component

AbstractWe attempted to calculate the breakaway stress σb of dislocation from attractive junction made by reaction of dislocations. Assuming that the force f acting on the unit length of dislocation with the Burgers vector B under a shear stress τa is f τ∣b˝∣ where b˝ is the phonon component of B, and that the elastic energy per unit length of dislocation W is approximated by W = G(∣b˝∣2 + c2 ∣b˔∣2) where G is the shear modulus, b˔ the phason component of B and c2 a coefficient of about 3.1 × 10−3. Using the values G = 48.4 GPa at 1070 K, the Taylor factor M = 3 and the measured dislocation density of 1.8 × 1013 m−2, we calculated σb for 21 possible dislocation reactions. Picking up the most possible dislocation reactions, σb distributed between 50 and 80 MPa, and the average of them was 64 MPa. This result strongly suggested the possibility that the main part of the internal stress of the high-temperature deformation of icosahedral Al-Pd-Mn is explained by σb.

Carbon-doped single-crystalline SiGe/Si thermistor with high temperature coefficient of resistance and low noise level

2010 ◽  
Vol 97 (22) ◽  
pp. 223507 ◽  
Author(s):  
H. H. Radamson ◽  
M. Kolahdouz ◽  
S. Shayestehaminzadeh ◽  
A. Afshar Farniya ◽  
S. Wissmar
Keyword(s):  
High Temperature ◽  
Temperature Coefficient ◽  
Noise Level ◽  
Low Noise ◽  
Temperature Coefficient Of Resistance ◽  
Single Crystalline ◽  
Carbon Doped

Advancements in Fast Epitaxial High-Temperature Brazing of Single-Crystalline Nickel-Base Superalloys

2009 ◽  
Author(s):  
Britta Laux ◽  
Sebastian Piegert ◽  
Joachim Ro¨sler
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Base Material ◽  
Secondary Phases ◽  
Single Crystalline ◽  
Thermodynamic Simulations ◽  
Nickel Base Superalloys ◽  
Stray Grains ◽  
Nickel Base ◽  
Nickel Manganese

High temperature diffusion brazing is a very important technology for filling cracks in components from single-crystalline nickel-base superalloys as used in aircraft engines and stationary gas turbines: alloys, which are similar to the base material, are enhanced by a fast diffusing melting-point depressant (MPD) like boron or silicon, which causes solidification by diffusing into the base material. Generally, epitaxial solidification of single-crystalline materials can be achieved by use of conventional braze alloys, however, very long hold times are necessary to provide a complete diffusion of the MPD out of the braze gap. If the temperature is lowered before diffusion is completed, brittle secondary phases precipitate, which serve as nucleation sites for stray grains and, therefore, lead to deteriorating mechanical properties. It was demonstrated in earlier works that nickel-manganese-based braze alloys are appropriate systems for the braze repair of particularly wide gaps in the range of more than 200 μm, which allow a significant shortening of the required hold times. This is caused by the complete solubility of manganese in nickel: epitaxial solidification can be controlled by cooling in addition to diffusion. In this work, it will be shown that the nickel-manganese-based systems can be enhanced by chromium and aluminium, which is with regard to high-temperature applications a very important aspect. Furthermore, it will be demonstrated that silicon, which could be identified as appropriate secondary MPD in recent works, can be replaced by titanium, as this element has additionally a γ′ stabilizing effect. Several braze alloys containing nickel, manganese, chromium, aluminium and titanium will be presented. Previously, the influence of the above mentioned elements on the nickel-manganese-based systems will be visualized by thermodynamic simulations. Afterwards, different compositions in combination with a heat treatment, which is typical for nickel-base superalloys, will be discussed: a microstructure, which is very similar to that within the base material can be presented.

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