The development of new materials requires penetrating insight into their deformation mechanisms. Material computation makes contributions to such understandings, especially for the processes that are hardly reachable experimentally, what's more, it exhibits a combination of high efficiency and convenience. Plasticity is one of the most important mechanical behaviors of metals. Plastic deformation is mainly carried by dislocation motion and deformation twinning. The α-phase is the major part of most high-temperature titanium alloys, and it has important contributions to the good high temperature performance. The dislocation mobility and their interactions have a great impact on the strength, creep, fatigue and fracture. Thus, the investigation of the dislocation behavior in α-Ti may help the improvement of the properties of titanium alloys. In this thesis, -type dislocations of different characters and on different slip planes were constructed and MD simulations carried out to investigate their movement and the interactions between them. The -type dislocations with Burgers vector of 1/3[11-20] are the most commonly observed in α-Ti, and their movements and interactions with other dislocations play a very important role in plastic deformation. The simulations of the stress strain behavior of the edge and screw dislocations on different slip systems show that, the existence of dislocations can greatly bring down the yield strength of the crystal. The simulation of screw dislocations shows that there are two types of core dissociation, the basal and prismatic, which favors the basal and the prismatic slip respectively. A further simulation shows that they can transform to each other under certain stress condition. The CRSS for the dislocation motion on the basal and prismatic planes are calculated. The investigation of the stress strain behavior of edge dipoles with different heights shows that the breaking stress of a dipole is strongly dependent on the dipole height, the breaking stress goes down as dipole height increased. The MD calculation results were compared with the curves derived from the elastic theory and a good agreement is found for large height dipole. The simulation of shearing under different temperatures shows that, temperature do not affect strongly the breaking stress of edge dipoles. Simulation of intersection of edge dislocations on the basal and prismatic plane show that, kinks that bear a screw property can be formed. The kink formation can be an obstacle to moving dislocations and can make contributions to strain hardening. Key words: dislocation, α-Ti, dipole, MD simulation, interaction, stacking fault, CRSS
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