Method for Fabricating Depth-Specific TEM In Situ Tensile Bars

The growing use of ion irradiation to assess degradation of nuclear materials has created a need to develop novel methods to probe the mechanical response of shallow ion-irradiated layers. Transmission electron microscopy (TEM) in situ mechanical testing can isolate the ion-irradiated layer from its unirradiated substrate. However, there is a lack of established procedures for preparing TEM in situ mechanical testing specimens from bulk materials requiring depth-specific examination, e.g., target dose on the ion irradiation damage profile. This study demonstrates a new method for extracting depth-specific TEM in situ tensile bars from a bulk specimen of Fe-5 wt.%Mo. Measured yield stress, ultimate tensile stress, Young’s modulus, and elongation are consistent with those properties obtained from similarly sized Fe and Mo single-crystal nanowires. Results are discussed in the context of the specimen size effect.