Simulation Of Movement And The Annihilation Process Of Grain Boundary Dislocations Force Using Phase Field Crystals

Phase field crystal model is proposed as a new simulation method of material microstructure in recent years which has drawn wide attention.This method not only overcomes the shortcomings of the traditional phase field method can not describe the evolution of microstructure defects from the atomic level, but exceeds the10-12s molecular dynamics method to simulate the time scale,which has a huge advantage for microstructure evolution in micro scale.At present, the phase field crystal method has developed rapidly at home and abroad, such as in the simulation of grain growth, heteroepitaxial growth, crack growth and achieved a series of important results.The grain boundary structure and dislocation movement in this paper is to simulate the grain sample six dimensional lattice from different temperature conditions with phase field crystals model which help to observe the face centered cubic lattice{111} surface line defect motion under external force in the actual experiment.The main conclusions are as follows:1.More dislocations formed at the grain boundaries if there grain orientation angle were greater in the grain samples.When the grain orientation angle is less than16degrees, the dislocation grain samples formed at the grain boundaries of the arrangement can use small angle dislocation arrangement rules to explain.When the grain orientation angle is greater than16degrees, the number of dislocations grain samples formed at the grain boundaries is various, complex arrangement, which could not be explained by the above rules.2.The stress test can be found in the grain samples each grain orientation on the angle under the condition of low temperature, dislocation separated form by each2groups of dislocation separate annihilation to every single group separation transition dislocation annihilation.When the grain orientation angle is28degrees, grain boundary in the "sawtooth" shape in the dislocation climbing mechanism, and in the "sawtooth" condyle dislocation to the interior of the grain position separated firstly.3.In the high temperature condition of dislocation motion is more rapid, and has more complex forms.When the grain orientation angle is8degrees, the grain samples of dislocations in the isolated did not immediately annihilate each other away after the interior slip to grain, but first reacted with not isolated dislocation.When the grain orientation angle is16degrees, the grain samples dislocation separated one partial slip to the grain interior annihilation disappeared first, the other part in the grain boundary generate dislocation again and then separate.4.Process of dislocation separation occurs is the process of grain orientation angle gradually reduced, also the total free system can continuously decreases.