TEM analysis of recrystallized double forged tungsten after exposure in JUDITH 1 and JUDITH 2. (December 2016)

• Record Type: Journal Article
• Authors: Van Renterghem, W.; Uytdenhouwen, I.; Loewenhoff, Th.; Wirtz, M.
• Is Part Of: Nuclear materials and energy. Volume 9(2016)
• Page Start: 484
• Page End: 489
• Publication Date: 2016-12
• Subjects: Tungsten -- Edge localized mode -- Transmission electron microscopy; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2016.04.003
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: TEM investigation of recrystallized pure tungsten after electron beam exposure to simulate ELMs. Low energy deposition to study the initial defects that are formed. No small-angle grain boundaries were formed, only line dislocations Number of defects as a result of thermal stresses increases with the number of pulses. Even if no macroscopic damage is detectable, ELMs create permanent damage which is the beginning of a high cycle fatigue process. Abstract: Five samples of recrystallized pure tungsten were exposed to transient heat loads using the electron beam of the JUDITH 1 and JUDITH 2 installations of Forschungszentrum Jülich. The heat flux and base temperature were the same for all samples; only the number of pulses and exposure device differed. Transmission electron microscopy was applied to determine the first defects that are introduced during exposure and to compare the effects of the two machines. With increasing number of pulses, first dislocations are formed near the grain boundaries, and then line dislocations and clusters of dislocations appear within the grains. Upon prolonged exposure, the dislocations migrate and cluster in dislocation pile-ups. Comparing exposure in JUDITH 1 to JUDITH 2, the amount of defects is much higher in the samples exposed in JUDITH 1.