Effect Of Crystal Defects On Damping Properties Of TiAl Coatings

TiAl alloy coatings have become one of the materials of choice for aero-engine blade damping coatings due to their good noise reduction and vibration dissipation.Since the damping properties of the coating are closely related to its own internal defects,this paper explores the vibration reduction mechanism of TiAl alloy coating from the microscopic point of view.In this paper,the crystal model with vacancy defects,dislocation defects,grain boundary defects and microcrack defects and the perfect defect-free crystal model are established by using Materials Studio software.They are relaxed using the conjugate gradient minimum energy algorithm to obtain the five models.Balanced configuration.The LAMMPS molecular dynamics simulation software was used to simulate the tensile simulation of the five models in the x-axis direction,and the variation law of internal defect atoms was observed by Atomeye visualization software.The simulation results show that the damping performance of the model containing crystal defects The damping properties of the perfect defect-free crystal model are better than those of the crystal defect model.The order of damping performance from high to low is vacancies,dislocations,microcracks and grain boundaries.It can be seen from the microscopic configuration of the internal defect atoms of different crystal defect models that the new defects are mainly dislocation defects,and they are continuously emitted,climbed and slipped from the initial defect sites,and finally spread throughout the model.In this process,energy is continuously dissipated,which affects the damping performance.In addition,the same external load tensile loading and unloading simulation calculations were carried out at four temperatures of 700 K,800K,900 K and 1000 K.It can be seen from the comparison of the simulation results that the damping performance of the model with vacancy defects and twin crystal defects is small at different temperatures.The damping properties of the model containing dislocation defects and microcrack defects are large at different temperatures.