[Table of Contents]

Plasma and Fusion Research

Volume 8, 1405006 (2013)

Regular Articles

Bend Stress Relaxation of Pure Tungsten
Kenta SASAKI, Shuhei NOGAMI, Makoto FUKUDA, Kiyohiro YABUUCHI and Akira HASEGAWA
Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
(Received 11 August 2012 / Accepted 18 November 2012 / Published 13 February 2013)

Abstract

Tungsten is one of the candidate materials being considered for fabricating the plasma facing components (PFCs) of fusion reactors. When used in fusion reactors, PFCs are exposed to high heat loads from the fusion plasma, resulting in the PFCs being subjected to induced thermal stresses. This study focused on the creep deformation of pure tungsten under such a deformation-controlled thermal stress. Bend stress relaxation (BSR) tests were performed on specimens of as-received pure tungsten at temperatures of 600 - 1000° C for 0.1 - 1 h in vacuum. The BSR ratio decreased with an increase in the temperature, decreasing sharply in a short period of 0.1 h and then decreasing gradually. Most of the stress was relieved during the BSR test performed at 1000° C for 1 h. The activation energy of stress relaxation, calculated using the cross-cut method, was similar to that of the Peierls mechanism. This suggested that the mobility of the dislocations controls the stress relaxation mechanism. Most of the stress was relieved quickly because the activation energy of stress relaxation was relatively small.

Keywords

tungsten, stress relaxation, creep, BSR method, dislocation

DOI: 10.1585/pfr.8.1405006

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This paper may be cited as follows:

Kenta SASAKI, Shuhei NOGAMI, Makoto FUKUDA, Kiyohiro YABUUCHI and Akira HASEGAWA, Plasma Fusion Res. 8, 1405006 (2013).