Fig. 1. Ordered dislocation loops in irradiated Ni. (a) Bright field and (b) dark field image of dislocation loops. Ordered dislocation loops are aligned roughly along the (110) plane. (c) Highlight of isolated dislocation loops with an average size of 4.1 nm.

Fig. 2. Microstructural evolution in tensile of small-volume Ni along [335]. (a) Frequent strain bursts in the stress-strain curve. (b)-(e) Dark field images showing evolution of DFCs under straining. (b) DFC nucleation, (c) DFC growth, (d) multiple DFC propagation and (e) DFC thickening.

Fig. 3. Line dislocation formation and sweep away. (a)-(c) Dislocation loops migrate, interact and merge into line dislocations. (d)-(f) Interactions of line dislocations and dislocation loops under straining: pinning of line dislocation, cleaning of dislocation loops and cross-slip of dislocation 2 because of pile-up.

Fig. 4. Microstructures inside DFC. (a) Ultrathin DFC lines along (111) after loading. The inset shows the ordered loops before loading. (b) Dislocation debris inside DFC and slip steps at edge. (c) Dark field image of DFC from sample in Fig. 2.

Fig. 5. Cartoon of the formation mechanism of DFC. (a) Nucleation of line dislocation by loops merging and spreading. (b) Pining of line dislocations by loops. (c) Cleaning of loops by line dislocation to form DFCs and thickening of DFCs by multiple dislocation sources operation and dislocation cross-slip.