Fig. 2: Twinning events in the Mg pillars with different stress gap magnitudes.
From: Visualization and validation of twin nucleation and early-stage growth in magnesium
a–g twin growth in the conventional pillar with the width of 750 nm under a homogenous stress field: a–d evolution of twin with indentation time; e corresponding compression curves; f enlarged TEM image of the final twin; g HRTEM images of basal/prismatic terraced boundary. h–o Nucleation and initial growth of one twin nucleus in the truncated wedge-shaped pillar with the top width of 250 nm under a medium stress difference: h–k evolution of twin nucleus with indentation time; l corresponding compression curves; m enlarged TEM image of the final twin; HRTEM images of n basal/prismatic terraced boundary, and o twin tip. The yellow dashed lines in g, n–o indicate the basal-prismatic interfaces with the basal plane of the matrix parallel to the prismatic plane of the twin and the red lines in g, n–o indicate the prismatic-basal interfaces with the prismatic plane of the matrix parallel to the basal plane of the twin. The max. stress curve in l was calculated by the ratios of compression loading to the cross section of the pillar top. The min. stress curve in l was calculated by the ratios of compression loading to the cross section of the pillar bottom. The value of 104 MPa in l shows the stress gap at the twin nucleation point h.
