Interaction between Dislocation and Twinning Boundary under Incremental Loading in alpha-Titanium

XY Liu and H Zhang and XL Cheng, CHINESE PHYSICS LETTERS, 35, 116201 (2018).

DOI: 10.1088/0256-307X/35/11/116201

The lattice dislocation interacting with grain boundary in the polycrystal exerts an evident influence on the materials' strength and toughness. A comprehensive study regarding the dislocation-twinning boundary (TB) interaction in a-titanium and TB migration is performed by employing molecular dynamic simulation. We analyze the interactions between dislocation and TB, under the conditions of plastic deformation and thermal stress, including the interaction between pure edge < a > dislocation and (11 (2) over bar2) TB and the interaction between mixed type < a > dislocations (10 (1) over bar1) TB at 10 K/300 K. The < c + a > pyramidal transmitting slip mode is motivated in the case of edge dislocation-(11 (2) over bar2) interaction at 300 K and then transforms into basal-dissociated dislocation after experiencing the complex dissociation and combination. The basal-dissociated pyramidal partial dislocation located in the second grain can be driven to penetrate through the second grain leaving the multiple stacking faults behind. Dissociation of incident basal dislocation on (10 (1) over bar1) TB results in a nucleation of a (10 (1) over bar1) twin embryo in twin crystals at room temperature. We determine the nature of the generated defects by means of the Burgers circuit analysis.

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