Effects of neutron irradiation of Ti3SiC2 and Ti3AlC2 in the 121-1085 °C temperature range

JOURNAL OF NUCLEAR MATERIALS

卷:484

Article

Tallman, Darin J.¹  He, Lingfeng²  Gan, Jian²  Caspi, El'ad N.^1,3  Hoffman, Elizabeth N.⁴  Barsoum, Michel W.¹ 

[1] Drexel Univ, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA

[2] Idaho Natl Lab, Idaho Falls, ID 83415 USA

[3] Nucl Res Ctr Negev, Dept Phys, IL-84190 Beer Sheva, Israel

[4] Savannah River Natl Lab, Savannah River Site, Aiken, SC 29808 USA

关键词: Ti3SiC2;    Ti3AlC2;    MAX phases;    Neutron irradiation;    Dislocation loops;   

DOI  :  10.1016/j.jnucmat.2016.11.016

来源: Elsevier

【 摘 要 】

Herein we report on the formation of defects in response to neutron irradiation of polycrystalline Ti3SiC2 and Ti3AlC2 samples exposed to total fluences of approximate to 6 x 10(20) n/m(2), 5 x 10(21) n/m(2) and 1.7 x 10(22) n/m(2) at irradiation temperatures of 121(12), 735(6) and 1085(68)degrees C. These fluences correspond to 0.14, 1.6 and 3.4 dpa, respectively. After irradiation to 0.14 dpa at 121 degrees C and 735 degrees C, black spots are observed via transmission electron microscopy in both Ti3SiC2 and Ti3AlC2. After irradiation to 1.6 and 3.4 dpa at 735 degrees C, basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in Ti3SiC2 , with loop diameters of 21(6) and 30(8) nm after 1.6 dpa and 3.4 dpa, respectively. In Ti3AlC2, larger dislocation loops, 75(34) nm in diameter are observed after 3.4 dpa at 735 degrees C, in addition to stacking faults. Impurity particles of TiC, as well as stacking fault TiC platelets in the MAX phases, are seen to form extensive dislocation loops under all conditions. Cavities were observed at grain boundaries and within stacking faults after 3.4 dpa irradiation, with extensive cavity formation in the TiC regions at 1085 degrees C. Remarkably, denuded zones on the order of 1 gm are observed in Ti3SiC2 after irradiation to 3.4 dpa at 735 degrees C. Small grains, 3-5 mu m in diameter, are damage free after irradiation at 1085 degrees C at this dose. The results shown herein confirm once again that the presence of the A-layers in the MAX phases considerably enhance their irradiation tolerance. Based on these results, and up to 3.4 dpa, Ti3SiC2 remains a promising candidate for high temperature nuclear applications as long as the temperature remains >700 degrees C. (C) 2016 Elsevier B.V. All rights reserved.

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