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Title: Effect of neutron irradiation on defect evolution in Ti3SiC2 and Ti2AlC

Here, 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 °C or 695 ± 25 °C, and up to 0.4 dpa at 350 ± 40 °C. Black spots are observed in both Ti3SiC2 and Ti2AlC after irradiation to both 0.1 and 0.4 dpa at 350 °C. After irradiation to 0.1 dpa at 695 °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 × 1023 loops/m3, the dislocation loop density in Ti2AlC was ≈1.5 orders of magnitude greater than in Ti3SiC2, at 3 x 1021 loops/m3. After irradiation at 350 °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, Ti3SiC2more » appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti2AlC.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [3] ;  [1]
  1. Drexel Univ., Philadelphia, PA (United States)
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  3. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
1236713
Report Number(s):
INL/JOU--15-34198
Journal ID: ISSN 0022-3115; PII: S0022311515302786
Grant/Contract Number:
AC07-051D14517
Type:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 468; Journal Issue: C; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Research Org:
Idaho National Laboratory, Idaho Falls, ID (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Ti3SiC2; Ti2AlC; MAX phases; neutron irradiation; dislocation loops