Abstract Abnormal grain growth of polycrystalline iron (Fe) foil up to grains of 1 cm × 2.2 cm in size, is reported. Pre-strain generated by plastic deformation promoted the abnormal grain growth during post-strain annealing, resulting in large area regions close to single crystal within the foil. The number of nucleus/nuclei and maximum grain size for the abnormal grain growth were highly affected by the plastic deformation conditions as they cause different stored energies in the foils. These stored energies were estimated from the intragranular orientation spread using electron back scatter diffraction, and the relationship between this spread and the abnormal grain growth was investigated.
Last. Kaihui Liu(PKU: Peking University)H-Index: 50
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The development of two-dimensional (2D) materials has opened up possibilities for their application in electronics, optoelectronics and photovoltaics, because they can provide devices with smaller size, higher speed and additional functionalities compared with conventional silicon-based devices1. The ability to grow large, high-quality single crystals for 2D components—that is, conductors, semiconductors and insulators—is essential for the industrial application of 2D devices2–4. Atom-layered he...
Single-crystal metals have distinctive properties owing to the absence of grain boundaries and strong anisotropy. Commercial single-crystal metals are usually synthesized by bulk crystal growth or by deposition of thin films onto substrates, and they are expensive and small. We prepared extremely large single-crystal metal foils by “contact-free annealing” from commercial polycrystalline foils. The colossal grain growth (up to 32 square centimeters) is achieved by minimizing contact stresses, re...
Last. Rodney S. Ruoff(UNIST: Ulsan National Institute of Science and Technology)H-Index: 165
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Fast-growth of single crystal monolayer graphene by CVD using methane and hydrogen has been achieved on “homemade” single crystal Cu/Ni(111) alloy foils over large area. Full coverage was achieved in 5 min or less for a particular range of composition (1.3 at.% to 8.6 at.% Ni), as compared to 60 min for a pure Cu(111) foil under identical growth conditions. These are the bulk atomic percentages of Ni, as a superstructure at the surface of these foils with stoichiometry Cu6Ni1 (for 1.3 to 7.8 bul...
#1Rickard Shen(KTH: Royal Institute of Technology)H-Index: 3
#2Pål Efsing(KTH: Royal Institute of Technology)H-Index: 12
Abstract Plastic strain estimation using electron backscatter diffraction (EBSD) based on kernel average misorientation (KAM) is affected by random orientation measurement error, EBSD step length, choice of kernel and average grain size. These sensitivities complicate reproducibility of results between labs, but it is shown in this work how these drawbacks can be overcome. The modifications to KAM were verified against a similar misorientation metric based on grain orientation spread (GOS), whic...
Last. Young Hee Lee(SKKU: Sungkyunkwan University)H-Index: 126
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Single-crystalline artificial AB-stacked bilayer graphene is formed by aligned transfer of two single-crystalline monolayers on a wafer-scale. The obtained bilayer has a well-defined interface and is electronically equivalent to exfoliated or direct-grown AB-stacked bilayers.
The growth of single-layer graphene on Cu metal by chemical vapor deposition (CVD) is a versatile method for synthesizing high-quality, large-area graphene. It is known that high CVD temperatures, close to the Cu melting temperature (1083 °C), are effective for the growth of large graphene domains, but the growth dynamics of graphene over the high-temperature Cu surface is not clearly understood. We investigated the surface dynamics of the single-layer graphene growth by using heteroepitaxial Cu...
Last. Young Hee Lee(SKKU: Sungkyunkwan University)H-Index: 126
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Seamless stitching of graphene domains, on polished copper (111) is proved clearly not only at atomic scale by scanning tunnelling microscopy (STM) and transmission electron micoscopy (TEM), but also at the macroscale by optical microscopy after UV-treatment. Using this concept of seamless stitching, synthesis of 6 cm × 3 cm monocrystalline graphene without grain boundaries on polished copper (111) foil is possible, which is only limited by the chamber size.
We report the scalable growth of aligned graphene and hexagonal boron nitride on commercial copper foils, where each film originates from multiple nucleations yet exhibits a single orientation. Thorough characterization of our graphene reveals uniform crystallographic and electronic structures on length scales ranging from nanometers to tens of centimeters. As we demonstrate with artificial twisted graphene bilayers, these inexpensive and versatile films are ideal building blocks for large-scale...
Preface Chapter 1 Thermodynamic Concepts and Relationships 1.1 Introduction 1.2 Thermodynamic Concepts and Relationships 1.3 Thermodynamics of Single Component Systems 1.4. Thermodynamics of Multiple Component Systems 1.5 Thermodynamics of Alloys 1.6 Thermodynamics of Ideal Binary Solutions 1.7 Thermodynamics of Non-Ideal Binary Solutions 1.8 Experimental Determination of Thermodynamic Quantities of Binary Alloys Summary Chapter 2 Thermodynamics Analysis of Solidification Processes in Metals and...
Abstract We report the atmospheric pressure chemical vapor deposition (CVD) growth of single-layer graphene over a crystalline Cu(1 1 1) film heteroepitaxially deposited on c -plane sapphire. Orientation-controlled, epitaxial single-layer graphene is achieved over the Cu(1 1 1) film on sapphire, while a polycrystalline Cu film deposited on a Si wafer gives non-uniform graphene with multi-layer flakes. Moreover, the CVD temperature is found to affect the quality and orientation of graphene grown ...
#1Shuaishuai Du(HIT: Harbin Institute of Technology)H-Index: 7
#2Huijie Liu(HIT: Harbin Institute of Technology)H-Index: 17
Last. Li Zhou(HIT: Harbin Institute of Technology)H-Index: 15
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Abstract null null To widen the narrow friction stir welding (FSW) process window of TA5 alloy, titanium alloy supporting friction stir welding (TSFSW) is proposed. Both conventional FSW (CFSW) and TSFSW methods were employed to reveal the formation mechanism of cavity defect, clarify the microstructure evolution in the weld and investigate the performance of TSFSW. Results showed that the prior β grains below the cavity defect were much smaller than the above and a clear converging line of mate...
Last. Yongxiao Wang(SDU: Shandong University)H-Index: 5
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Abstract The porthole die extrusion processes of 2196 Al-Cu-Li alloy were carried out at billet temperatures of 420~510 oC and ram speeds of 0.25~5.0 mm/s, then the extruded profiles were subjected to the solution and aging treatment. Abnormal grain growth (AGG) was observed along longitudinal weld of profiles during the extrusion and solution treatment. The fine equiaxed grains with Copper orientation were formed in the welding area when extruded at low temperature and low extrusion speed, and ...