Effect of neutron irradiation on defect evolution in Ti3SiC2 and Ti2AlC

JOURNAL OF NUCLEAR MATERIALS

卷:468

Article

Tallman, Darin J.¹  He, Lingfeng²  Garcia-Diaz, Brenda L.³  Hoffman, Elizabeth N.³  Kohse, Gordon⁴  Sindelar, Robert L.³  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] Savannah River Natl Lab, Aiken, SC 29808 USA

[4] MIT, Nucl Reactor Lab, Cambridge, MA 02139 USA

关键词: Ti3SiC2;    Ti2AlC;    MAX phases;    Neutron irradiation;    Dislocation loops;   

DOI  :  10.1016/j.jnucmat.2015.10.030

来源: Elsevier

【 摘 要 】

Herein we report on the characterization of defects formed in polycrystalline Ti3SiC2 and Ti2AlC samples exposed to neutron irradiation up to 0.1 displacements per atom (dpa) at 350 +/- 40 degrees C or 695 +/- 25 degrees C, and up to 0.4 dpa at 350 +/- 40 degrees C. Black spots are observed in both Ti3SiC2 and Ti2AlC after irradiation to both 0.1 and 0.4 dpa at 350 degrees C. After irradiation to 0.1 dpa at 695 degrees C, small basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in both materials. At 9 +/- 3 and 10 +/- 5 nm, the loop diameters in the Ti3SiC2 and Ti2AlC samples, respectively, were comparable. At 1 x 10(23) loops/m(3), the dislocation loop density in Ti2AlC was approximate to 1.5 orders of magnitude greater than in Ti3SiC2, at 3 x 10(21) loops/m(3). After irradiation at 350 degrees C, extensive microcracking was observed in Ti2AlC, but not in Ti3SiC2. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti3SiC2. The MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al2O3. Based on these results, Ti3SiC2 appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti2AlC. (C) 2015 Elsevier B.V. All rights reserved.

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