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Title: Effect of neutron irradiation on defect evolution in Ti 3SiC 2 and Ti 2AlC

Here, we report on the characterization of defects formed in polycrystalline Ti 3SiC 2 and Ti 2AlC 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 Ti 3SiC 2 and Ti 2AlC 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 Ti 3SiC 2 and Ti 2AlC samples, respectively, were comparable. At 1 × 10 23 loops/m 3, the dislocation loop density in Ti 2AlC was ≈1.5 orders of magnitude greater than in Ti 3SiC 2, at 3 x 10 21 loops/m3. After irradiation at 350 °C, extensive microcracking was observed in Ti 2AlC, but not in Ti 3SiC 2. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti 3SiC 2. Themore » MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al 2O 3. Based on these results, Ti 3SiC 2 appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti 2AlC.« less
Authors:
ORCiD logo [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:
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 Lab. (INL), 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
OSTI Identifier:
1236713
Alternate Identifier(s):
OSTI ID: 1359392