The time-of-flight Small-Angle Neutron Spectrometer at China Spallation Neutron Source

Ke, Yubin; He, Chunyong; Zheng, Haibiao; Geng, Yansheng; Fu, Jingzhu; Zhang, Shengkai; Hu, Hao; Wang, Songlin; Zhou, Bin; Wang, Fangwei; Tao, J.

doi:10.1080/10448632.2018.1514197

Cited by 54 publications

(22 citation statements)

References 3 publications

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“…The samples for TEM were first mechanically polished to 80 μm, followed by electrochemical polishing using a twin-jet polishing unit with a mixed solution of 33.3% methanol and 66.6% nitric acid at 22 V and 233 K. TEM observations were conducted using a JOEM-2100F operating at 200 kV and a high-resolution Cs-corrected FEI Titan 3 Themis at 300 kV. SANS was performed on a small angle neutron scattering instrument at the China Spallation Neutron Source [Ke et al, 2018].…”

Section: Experiments and Methodsmentioning

confidence: 99%

Experimental and modelling assessment of ductility in a precipitation hardening AlMgScZr alloy

Han

Chen

et al. 2021

International Journal of Plasticity

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Precipitation hardening is the most effective strategy to enhance the mechanical properties of metals. Dislocation mechanisms to control strengthening during precipitation have been demonstrated extensively. However, owing to the complexity of different precipitates in alloys, variations in ductility caused by precipitation are complex and have not been clarified so far. In this study, the effects of precipitation on ductility in precipitation hardening aluminium alloys are investigated based on a modified dislocation-based approach and experimental characterisation. The AlMgScZr alloy with spherical Al3(Sc, Zr) precipitates is used as a model alloy system to understand the effects of precipitation on ductility. Via heat treatment, shearable and nonshearable Al3(Sc, Zr) precipitates are introduced in the AlMg matrix. The results show that the ductility of AlMgScZr alloy decreases when shearable precipitates occur, while it increases with shearable precipitates being replaced by nonshearable precipitates. The variation in ductility of AlMgScZr alloy is mainly controlled by the dynamic recovery rate of the dislocations. Finally, by analysing the different precipitate-dislocation interactions and evaluating the dislocation density evolution during deformation, the dislocation mechanisms of 2 ductility during precipitation for AlMgScZr alloy are demonstrated. This study reveals the dislocation mechanism for controlling ductility during precipitation for AlMgScZr alloy which can provide a theoretical foundation for the design of high-performance structural materials.

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Section: Experiments and Methodsmentioning

confidence: 99%

Experimental and modelling assessment of ductility in a precipitation hardening AlMgScZr alloy

Han

Chen

et al. 2021

International Journal of Plasticity

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“…The SANS experiment was performed on the SANS instrument at China Spallation Neutron Source (CSNS) [Ke et al, 2018]. The detailed information about SANS and data fitting process can be found in reference [Chen et al, 2021].…”

Section: Methodsmentioning

confidence: 99%

The influence of shearable and nonshearable precipitates on the Portevin-Le Chatelier behavior in precipitation hardening AlMgScZr alloys

Chen

et al. 2021

International Journal of Plasticity

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The well-known mechanisms of interaction between precipitates and dislocations are shearing (for shearable precipitates) and bypassing mechanisms (for nonshearable precipitates). The transition from shearable to nonshearable precipitates in precipitation hardening alloys leads to changes of dislocation motion mode and dislocation multiplication behavior, which inevitably causes different PLC behaviors.In this study, we systematically investigate the influence of shearable and nonshearable Al3(Sc, Zr) precipitates on PLC behaviors by experimental characterization for precipitation hardening AlMgScZr alloys. We analyze the onset strain, critical strain-rate range, serration amplitude, and propagation behavior of PLC bands in detail for AlMgScZr alloys with shearable and nonshearable precipitates, respectively. We find that the transition from shearable to nonshearable precipitates changes the PLC band propagation behavior, decreases the magnitude of serration amplitude, expands the strain-rate range as well as decreases the critical strain rate between normal behavior (the critical strain increases with the increase of strain rate) and inverse behavior (the critical strain decreases with the increase of strain rate) regimes due to the different dislocation-precipitate interactions. Besides, the transition from shearable to nonshearable precipitates increases the onset strain at normal behavior while decreases the onset strain at inverse behavior depending on the different roles of precipitates in the solute-dislocation interaction. Finally, we reveal the nature of influence of different dislocation-precipitate interactions on PLC behavior considering different strengthening mechanisms based on quantitative characterization on precipitates and dislocation density.

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“…Energy-dispersive Xray spectroscopy (EDS) through a SEM and spherical aberration-corrected high-angle annular dark-field scanning TEM (HAADF-STEM, JEM ARM200CF) were performed to examine the elemental distribution at the microscale and nanoscale, respectively. To further confirm the structure of Fe-MGI, the small angle neutron scattering (SANS) measurements were carried out at the China Spallation Neutron Source (CSNS) [30]. Incident neutrons with wavelengths of 1-9 Å were selected using a double-disc bandwidth chopper, which was collimated to the sample by a pair of apertures.…”

Section: Materials Preparation and Characterizationmentioning

confidence: 99%

Excellent long-term reactivity of inhomogeneous nanoscale Fe-based metallic glass in wastewater purification

et al. 2019

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Metallic glasses (MGs) have attracted great attention in wastewater treatment because of their high reactivity arising from amorphous structure, large residual stress and high density of low coordination sites. However, the reactivity of MGs would gradually slow down with time due to the passivation of active sites by corrosion products, resulting in limited long-term reactivity, which is also an unsolved key issue for established crystalline zero valent iron (ZVI) technology. Here, such problems are successfully overcome by introducing nanoscale chemical inhomogeneities in Fe-based MG (Fe-MGI), which apparently contributes to local galvanic cell effect and accelerates electron transfer during degradation process. More importantly, the selective depletion of Fe 0 causes local volume shrinkage and crack formation, leading to self-peeling of precipitated corrosion products and reacted regions. Thereby fresh low coordination sites could be continuously provided, counteracting the mass transport and reactivity deteriorating problem. Consequently, Fe-MGI demonstrates excellent long-term reactivity and self-refreshing properties even in neutral solution. The present results provide not only a new candidate but also a new route of designing ZVI materials for wastewater treatment.

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The time-of-flight Small-Angle Neutron Spectrometer at China Spallation Neutron Source

Cited by 54 publications

References 3 publications

Experimental and modelling assessment of ductility in a precipitation hardening AlMgScZr alloy

Experimental and modelling assessment of ductility in a precipitation hardening AlMgScZr alloy

The influence of shearable and nonshearable precipitates on the Portevin-Le Chatelier behavior in precipitation hardening AlMgScZr alloys

Excellent long-term reactivity of inhomogeneous nanoscale Fe-based metallic glass in wastewater purification

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