Fig. 1. Microstructure and deformation snapshots of an Au nanowire with a twin-twin intersection.: (a) Initial structure of the as-fabricated Au nanowire with two conjugate twins denoted as T1 and T2, respectively, interlocked inside the intersection region. (b) Fast Fourier transform patterns of T1 and T2. Scale bar, 2 nm-1. (c) Enlarged region of T2 showing the high density of SFs existed in T2. Scale bar, 1 nm. (d) Transmission of T1 across T2. Insets showing the different widths of the initial and transmission segments of T1, as marked out by the white rectangles. (e) Thickening of T1 induced by the surface-emitted twinning partials, as evidenced by the surface steps shown in the inset. (f) Subsequent transmission of T2 across the T1, resulting in the de-twinning process of T1. (g) Eventual annihilation of T1 and further twin thickening of T2. The tensile loading was applied along the [001] direction, as shown by the red arrow in (a). Scale bars, 5 nm.

Fig. 2. Schematic illustration of a double Thompson tetrahedron. The top half represents the matrix slip systems and the bottom half represents the twin slip systems.

Fig. 3. HRTEM filter (without mask) image sequence showing the detailed procedure of T1 transmission across T2: (a) Initial transmission of T1 via the emission of SFs, as pointed out by the white arrows and shown in the inset. The Burgers vector of twinning partial in T2 is $\vec{b}$ = 1/6[$\bar{1}$12]. (b) Scenario of T1 transmission across barrier T2. The yellow dashed line in T2 represents the initial position of the TB. The numbers indicate the thickness of each twin segment. (c) Subsequent thickening of T2 by a cross-slip mechanism. Scale bars, 2 nm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 4. Twin thickening and de-twinning process of twin-twin intersection: (a-c) Deformation snapshots of the sequential one atomic layer twin thickening and de-twinning process. The Burgers vector of SF1 is $\vec{b}$ = 1/6[1$\bar{1}$2], as confirmed by the Burgers circuit in the enlarged image of the intersection in (b). The yellow dashed lines in (b) and (c) represent the TB positions before the twin thickening and de-twinning, respectively. A perfect dislocation was left on the ($\bar{1}$11) plane at the intersection region, as marked out by “T” in the enlarged image of the intersection in (c). Scale bars, 2 nm. (d-f) Schematics illustrating the twin thickening and de-twinning process observed in the experiment. SF1 glides along the ACD plane and T2 along the BCD planes. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 5. TEM image sequence showing the detailed procedure of T2 transmission across T1: (a) Intersection of T1 and T2 at TB1. The white arrows indicate the ledges on the TB of T2, corresponding to the partial dislocations αB. (b) Transmission of T2 across TB1, leading to the de-twinning of T1, as pointed out by the white arrows and the Burgers circuit in the corresponding enlarged image. (c) Further transmission of T2 across TB2 which resulted in the shear of T1. Scale bars, 2 nm. (d-f) Schematics illustrating of the transmission process presented in (a-c). T2 is assumed to glide along the BCD planes and T1 along the ABC planes.