Figure 4: Crack bridging via near-tip twinned nanobridges.
From: Nanoscale origins of the damage tolerance of the high-entropy alloy CrMnFeCoNi
(a) Bright-field TEM image of a growing crack during in situ straining of the CrMnFeCoNi high-entropy alloy, showing the formation of nano/submicron voids at the intersection of two slip systems, which then grow along two {111} slip bands (scale bar, 200 nm). The crack tip is located ∼500 nm away from the right-lower corner of this image. The inset in a is a schematic of the structure at the crack tip. (b) two TEM images captured from the in situ TEM movie (Supplementary Movie 6) that show the nanoscale tensile loading of nano ‘fibres’ that bridge the crack in the near-tip region (scale bar, 200 nm). Nanotwins can be seen to form in some of the fibres, enhancing their ductility and resulting in their significant elongation. (c) High-resolutionTEM image of deformation twinning taken during in situ TEM tensile test (scale bar, 5 nm). (d) HAADF-STEM image of the atomic structure of the deformation nanotwins, showing characteristic {111} twins (scale bar, 2 nm).
