Recrystallization and grain growth induced by ELMs-like transient heat loads in deformed tungsten samples

Tungsten has been chosen as the main candidate for plasma facing components (PFCs) due to its superior properties under extreme operating conditions in future nuclear fusion reactors such as ITER. One of the serious issues for PFCs is the high heat load during transient events such as ELMs and disru...

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Bibliographic Details
Published in:Scientific reports 2014-11, Vol.4 (1), p.6845-6845, Article 6845
Main Authors: Suslova, A., El-Atwani, O., Sagapuram, D., Harilal, S. S., Hassanein, A.
Format: Article
Language:English
Subjects:
147/137
147/143
639/166
639/301/1023/1026
Fusion reactors
Grain growth
Grain size
Growth rate
Heat
Humanities and Social Sciences
Mechanical properties
multidisciplinary
Particle size
Reactors
Science
Science & Technology - Other Topics
Temperature effects
Thermal stress
Transition temperatures
Tungsten
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Summary:Tungsten has been chosen as the main candidate for plasma facing components (PFCs) due to its superior properties under extreme operating conditions in future nuclear fusion reactors such as ITER. One of the serious issues for PFCs is the high heat load during transient events such as ELMs and disruption in the reactor. Recrystallization and grain size growth in PFC materials caused by transients are undesirable changes in the material, since the isotropic microstructure developed after recrystallization exhibits a higher ductile-to-brittle transition temperature which increases with the grain size, a lower thermal shock fatigue resistance, a lower mechanical strength and an increased surface roughening. The current work was focused on careful determination of the threshold parameters for surface recrystallization, grain growth rate and thermal shock fatigue resistance under ELM-like transient heat events. Transient heat loads were simulated using long pulse laser beams for two different grades of ultrafine-grained tungsten. It was observed that cold rolled tungsten demonstrated better power handling capabilities and higher thermal stress fatigue resistance compared to severely deformed tungsten. Higher recrystallization threshold, slower grain growth and lower degree of surface roughening were observed in the cold rolled tungsten.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep06845