Motion detection for TEM in situ indentation

TEM in situ indentation is one of the simplest TEM in situ mechanical testing configurations to fabricate and test.  However, interpretation of the results is extremely difficult, given the complex geometry of the indenter tip and thin specimen lamella.  Specimen vibration on contact with the Berkovich indenter tip blurs the TEM resolution video (left), further hindering the interpretation of these tests.

We have devised a novel heat mapping approach that identifies pixels that change from one frame to the next.  The heat map spectrum runs from red (most changed pixels) to blue (least changed pixels).  The heat map video, integrated over the course of the indentation test (right), helps us more clearly identify obstacles to dislocation motion and determine their relative strengths.  We can observe grain boundaries and irradiation-induced dislocation loops.

Collaborators:

  • S. Thomas, Boise State University
  • Y. Lu, Boise State University

Support:

  • US Nuclear Regulatory Commission award NRC-HQ-84-14-G-0056
  • DOE Nuclear Science User Facilities project 16-656

Products:

  1. J.P. Wharry, K.H. Yano, M.J. Swenson, and Y.Q. Wu.  TEM in situ mechanical testing techniques for ion irradiated materials.  13th International School on Degradation and Aging of Materials of Nuclear Power Units During Operation, Moscow Engineering Physics Institute, Moscow, Russia, October 2016.
  2. J.P. Wharry, K.H. Yano, M.J. Swenson, and Y.Q. Wu.  In situ TEM mechanical testing approaches for ion irradiated alloys.  International Conference on Plasticity, Puerto Vallarta, Mexico, January 2017.
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