A study of the effect of helium concentration and displacement damage on the microstructure of helium ion irradiated tungsten

JOURNAL OF NUCLEAR MATERIALS

卷:495

Article

Harrison, R. W.¹  Greaves, G.¹  Hinks, J. A.¹  Donnelly, S. E.¹ 

[1] Univ Huddersfield, Sch Comp & Engn, Huddersfield HD1 3DH, W Yorkshire, England

关键词: Tungsten;    Irradiation;    Fusion;    Radiation damage;    In situ TEM;   

DOI  :  10.1016/j.jnucmat.2017.08.033

来源: Elsevier

【 摘 要 】

Transmission electron microscopy (TEM) with in-situ He ion irradiation has been used to examine the damage microstructure of W when varying the helium concentration to displacement damage ratio, irradiation temperature and total dose. Irradiations employed 15, 60 or 85 keV He ions, at temperatures between 500 and 1000 degrees C up to doses of similar to 3.0 DPA. Once nucleated and grown to an observable size in the TEM, bubble diameter as a function of irradiation dose did not measurably increase at irradiation temperatures of 500 degrees C between 1.0 and 3.0 DPA; this is attributed to the low mobility of vacancies and He/vacancy complexes at these temperatures. Bubble diameter increased slightly for irradiation temperatures of 750 degrees C and rapidly increased when irradiated at 1000 degrees C. Dislocation loops were observed at irradiation temperatures of 500 and 750 degrees C and no loops were observed at 1000 degrees C. Burgers vectors of the dislocations were determined to be b = +/- 1/2<111> type only and both vacancy and interstitial loops were observed. The proportion of interstitial loops increased with He-appm/DPA ratio and this is attributed to the concomitant increase in bubble areal density, which reduces the vacancy flux for both the growth of vacancy-type loops and the annihilation of interstitial clusters. (C) 2017 Elsevier B.V. All rights reserved.

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