Study on micro-crack propagation behavior of single-crystal α-Ti under shear stress based on molecular dynamics

In order to reveal the micro-crack behavior of single-crystal titanium under nanoscale shear stress conditions, a molecular dynamics model of single-crystal titanium was constructed. Shear force is applied to the single-crystal titanium model on 000112¯10 crystal orientation and 1¯0101¯21¯0 crystal orientation, respectively. The crystal structure is analyzed by Common Neighbor Analysis (CNA) method and Dislocation Extraction Algorithm (DXA) to identify defects and dislocations which reveal the microstructure evolution mechanism of single-crystal titanium. The results show that under the action of shear stress, the dislocation of single-crystal titanium is mainly formed in the crack area and the dislocation moves completely along the direction of the shear force. When the shear force is applied on 000112¯10 crystal orientation, the formation of dislocations is accompanied by a largescale phase change and the proliferation mode of dislocation is single point Frank-Read source. When the shear force is applied on 1¯0101¯21¯0 crystal orientation, the crystal dislocation is first generated in the crack region, and the proliferation mode of dislocation is dynamic proliferation mechanism. Then dislocation occurs at the corner of the material and continuous slip occurs in the atomic layer, which seriously affects the shear resistance of the single-crystal α-Ti.