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Title: Toward high-throughput defect density quantification: A comparison of techniques for irradiated samples

Journal Article · · Ultramicroscopy
 [1];  [1]; ORCiD logo [2];  [1]; ORCiD logo [3];  [4]; ORCiD logo [3];  [5]
  1. Drexel Univ., Philadelphia, PA (United States)
  2. Drexel Univ., Philadelphia, PA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. Drexel Univ., Philadelphia, PA (United States); Johns Hopkins Univ., Baltimore, MD (United States)
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Transmission electron microscopy (TEM) is an established tool used for the investigation of defects in materials. Traditionally, diffraction contrast techniques—two-beam bright-field and weak-beam dark-field—have been used to image defects due to contrast sensitivity from weak lattice strains. Use of these methods entail an intricate tilt series of imaging using different diffracting vectors, g, to verify the g•b invisibility criterion relative to the different defect types and habit planes inherent to the material. Recently, the addition of down-zone imaging and STEM imaging has also proven to be effective imaging techniques for defect density analysis. Interest in nanocrystalline (NC) materials, spurred by their conjectured superior properties compared to their coarse-grain counterparts, has been thriving and the investigation of their defect morphologies is essential. Maneuvering within NC samples in the TEM adds another layer of difficulty making the aforementioned techniques not practical for application to specimens with complex microstructures. For this reason, we have devised a protocol for identifying NC grains optimally oriented for quantitative analysis using NanoMegas ASTAR automated crystal orientation mapping (ACOM) in the TEM. In this work, we conduct a series of experiments assessing the effectiveness of conventional two-beam bright-field, weak-beam dark-field, and down-zone STEM imaging. Here, we also evaluate an ACOM-assisted multibeam imaging method and compare defect density results obtained using each technique in an irradiated nanocrystalline Au sample.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
89233218CNA000001; AC02-06CH11357; AC52-06NA25396
OSTI ID:
1570621
Alternate ID(s):
OSTI ID: 1616282; OSTI ID: 1702697
Report Number(s):
LA-UR-19-21178
Journal Information:
Ultramicroscopy, Vol. 206, Issue C; ISSN 0304-3991
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

Figures / Tables (8)

Table 1(p. 9)table Table 1
Figure 1(p. 11)figure Figure 1
Figure 2(p. 15)figure Figure 2
Figure 3(p. 16)figure Figure 3
Figure 4(p. 18)figure Figure 4
Figure 5(p. 20)figure Figure 5
Figure 6(p. 22)figure Figure 6
Figure 7(p. 24)figure Figure 7

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Related Subjects

36 MATERIALS SCIENCE
Irradiation damage
Nanocrystalline
Transmission electron microscopy
Defect density
Automated crystal orientation mapping