scholarly journals Texture evolution and mechanical behaviour of irradiated face-centred cubic metals

2018 ◽  
Vol 474 (2210) ◽  
pp. 20170604 ◽  
Author(s):  
L. R. Chen ◽  
X. Z. Xiao ◽  
L. Yu ◽  
H. J. Chu ◽  
H. L. Duan
Keyword(s):  
Mechanical Behaviour ◽  
Crystallographic Texture ◽  
Texture Evolution ◽  
Polycrystalline Materials ◽  
Irradiation Hardening ◽  
Cubic Metals ◽  
Physically Based ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Good Agreement

A physically based theoretical model is proposed to investigate the mechanical behaviour and crystallographic texture evolution of irradiated face-centred cubic metals. This model is capable of capturing the main features of irradiated polycrystalline materials including irradiation hardening, post-yield softening and plasticity localization. Numerical results show a good agreement with experimental data for both unirradiated and irradiated stress–strain relationships. The study of crystallographic texture reveals that the initial randomly distributed texture of unirradiated metals under tensile loading can evolve into a mixture of [111] and [100] textures. Regarding the irradiated case, crystallographic texture develops in a different way, and an extra part of [110] texture evolves into [100] and [111] textures. Thus, [100] and [111] textures become dominant more quickly compared with those of the unirradiated case for the reason that [100] and [111]-oriented crystals have higher strength, and their plastic deformation behaviours are more active than other oriented crystals. It can be concluded that irradiation-induced defects can affect both the mechanical behaviour and texture evolution of metals, both of which are closely related to irradiation hardening.

scholarly journals Hardening and Creep of Ion Irradiated CLAM Steel by Nanoindentation

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Ying Liu ◽  
Wenbin Liu ◽  
Long Yu ◽  
Lirong Chen ◽  
Haonan Sui ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Primary Creep ◽  
Steady State Creep ◽  
Indentation Creep ◽  
Metallic Materials ◽  
Irradiation Hardening ◽  
Clam Steel ◽  
Large Numbers ◽  
Induced Defects ◽  
Irradiation Induced Defects

Ion irradiation, combined with nanoindentation, has long been recognized as an effective way to study effects of irradiation on the mechanical properties of metallic materials. In this research, hardening and creep of ion irradiated Chinese low activation martensitic (CLAM) steel are investigated by nanoindentation. Firstly, it is demonstrated that ion irradiation results in the increase of hardness, because irradiation-induced defects impede the glide of dislocations. Secondly, the unirradiated CLAM steel shows indentation creep size effect (ICSE) that the indentation creep strain decreases with the applied load, and ICSE is found to be associated with the variations of geometrical necessary dislocations (GNDs) density. However, ion irradiation results in the alleviation of ICSE due to the irradiation hardening. Thirdly, ion irradiation accelerates nanoindentation creep due to the large numbers of irradiation-induced vacancies whose diffusion controls creep deformation. Meanwhile, owing to the annihilation of vacancies, ion irradiation has a significant influence on the primary creep while only negligible influence has been observed for the steady-state creep.

Irradiation Damage and Embrittlement in RPV Steels Under the Aspect of Long Term Operation: Overview of the FP7 Project LONGLIFE

2010 ◽  
Author(s):  
Eberhard Altstadt ◽  
Frank Bergner ◽  
Hieronymus Hein
Keyword(s):  
Cluster Formation ◽  
Irradiation Damage ◽  
Irradiation Embrittlement ◽  
Irradiation Hardening ◽  
Term Operation ◽  
Weld Material ◽  
Project Structure ◽  
Induced Defects ◽  
Irradiation Induced Defects

The increasing age of the European NPPs and envisaged lifetime extensions up to 80 years require an improved understanding of RPV irradiation embrittlement effects connected with long term operation (LTO). Phenomena which might become important at high neutron fluences (such as late blooming effects and flux effects) must be considered adequately in the safety assessments. Therefore the project LONGLIFE was initiated within the 7th Framework Programme of the European Commission. The project aims at: i) improved knowledge on LTO phenomena relevant for European reactors; ii) assessment of prediction tools, codes, standards and surveillance guidelines. In the paper, we give an overview of the project structure and the related tasks. Furthermore we present two examples for the experimental evidence of LTO relevant phenomena: the first example is related to the flux dependence of defect cluster formation in a neutron irradiated weld material. We have found that the size of the irradiation induced defects exhibits a flux effect whereas the mechanical properties are almost independent of the flux. The second example refers to the acceleration of irradiation hardening after exceeding a threshold fluence. This effect was observed by means of both small angle neutron scattering (SANS) and tensile testing for low Cu RPV steels irradiated at a temperature of 255 °C. These examples demonstrate that LTO irradiation effects have to be investigated in more detail to guarantee the applicability of the embrittlement surveillance guidelines beyond 40 years of operation.

scholarly journals Fundamental Mechanisms for Irradiation-Hardening and Embrittlement: A Review

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1132 ◽  
Author(s):  
Xiazi Xiao
Keyword(s):  
Material Properties ◽  
Interaction Process ◽  
Experimental Equipment ◽  
General Introduction ◽  
Irradiation Hardening ◽  
Testing Conditions ◽  
Defect Interaction ◽  
Dislocation Defect ◽  
Induced Defects ◽  
Irradiation Induced Defects

It has long been recognized that exposure to irradiation environments could dramatically degrade the mechanical properties of nuclear structural materials, i.e., irradiation-hardening and embrittlement. With the development of numerical simulation capability and advanced experimental equipment, the mysterious veil covering the fundamental mechanisms of irradiation-hardening and embrittlement has been gradually unveiled in recent years. This review intends to offer an overview of the fundamental mechanisms in this field at moderate irradiation conditions. After a general introduction of the phenomena of irradiation-hardening and embrittlement, the formation of irradiation-induced defects is discussed, covering the influence of both irradiation conditions and material properties. Then, the dislocation-defect interaction is addressed, which summarizes the interaction process and strength for various defect types and testing conditions. Moreover, the evolution mechanisms of defects and dislocations are focused on, involving the annihilation of irradiation defects, formation of defect-free channels, and generation of microvoids and cracks. Finally, this review closes with the current comprehension of irradiation-hardening and embrittlement, and aims to help design next-generation irradiation-resistant materials.

C ions irradiation induced defects analysis and effects on optical properties of TiO2 Nanoparticles

2021 ◽  
Vol 863 ◽  
pp. 158635
Author(s):  
Afsheen Farooq ◽  
Samson O. Aisida ◽  
Abdul Jalil ◽  
Chang-Fu Dee ◽  
Poh Choon Ooi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Tio2 Nanoparticles ◽  
Defects Analysis ◽  
Induced Defects ◽  
Irradiation Induced Defects

An Sem/Ebsd Study of Shear Bands Formation in Al-0.23%wt.Zr Alloy Deformed in Plane Strain Compression / Krystalograficzne Aspekty Formowania Sie Pasm Scinania W Stopie Al-0.23%Wag.Zr Odkształcanym W Próbie Nieswobodnego Sciskania

2013 ◽  
Vol 58 (1) ◽  
pp. 145-150 ◽  
Author(s):  
H. Paul ◽  
P. Uliasz ◽  
M. Miszczyk ◽  
W. Skuza ◽  
T. Knych
Keyword(s):  
Crystal Lattice ◽  
Grain Boundaries ◽  
Texture Evolution ◽  
Shear Bands ◽  
Shear Direction ◽  
Face Centered Cubic ◽  
Electron Backscattered Diffraction ◽  
Cubic Metals ◽  
Slip Planes ◽  
Face Centered

The crystal lattice rotations induced by shear bands formation have been examined in order to investigate the influence of grain boundaries on slip propagation and the resulting texture evolution. The issue was analysed on Al-0.23wt.%Zr alloy as a representative of face centered cubic metals with medium-to-high stacking fault energy. After solidification, the microstructure of the alloy was composed of flat, twin-oriented, large grains. The samples were cut-off from the as-cast ingot in such a way that the twinning planes were situated almost parallel to the compression plane. The samples were then deformed at 77K in channel-die up to strains of 0.69. To correlate the substructure with the slip patterns, the deformed specimens were examined by SEM equipped with a field emission gun and electron backscattered diffraction facilities. Microtexture measurements showed that strictly defined crystal lattice re-orientations occurred in the sample volumes situated within the area of the broad macroscopic shear bands (MSB), although the grains initially had quite different crystallographic orientations. Independently of the grain orientation, their crystal lattice rotated in such a way that one of the f111g slip planes became nearly parallel to the plane of maximum shear. This facilitates the slip propagation across the grain boundaries along the shear direction without any visible variation in the slip plane. A natural consequence of this rotation is the formation of specific MSB microtextures which facilitates slip propagation across grain boundaries.

Self-annihilation of electron-irradiation-induced defects in InAsxP1−x∕InP multiquantum well solar cells

2007 ◽  
Vol 90 (23) ◽  
pp. 233111 ◽  
Author(s):  
Aurangzeb Khan ◽  
A. Freundlich ◽  
Jihua Gou ◽  
A. Gapud ◽  
M. Imazumi ◽  
...  
Keyword(s):  
Solar Cells ◽  
Electron Irradiation ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Multiquantum Well
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