Study of nano-broaching properties on nickel-based high-temperature alloys based on molecular dynamics simulation

Broaching technology, as the preferred high-volume machining process for nickel-based high-temperature alloy turbine disk tongue and groove machining, directly determines the reliability and stability of the turbine disk during its service. Although a host of scholars have carried out extensive experimental studies on the broaching process, there are few reports on the exploration of the atomic scale response in the broaching process. In this paper, the plastic deformation, defect evolution and distribution, surface formation, and stress changes during nano broaching of nickel-based single-crystal alloys are analyzed based on the molecular dynamics simulation (MD) method to reveal their broaching properties. The results show that the thermal softening effect induced by the accumulation of cutting temperature is the main reason for the violent plastic deformation within the matrix. The phase transition of the matrix structure, the depth of the subsurface damage layer, and the dislocation density increase with the increase of the cutting distance at the initial stage of the broaching process, and then slow down the upward trend at the stable broaching stage, and fluctuate in a certain range gradually. Meanwhile, the sources of atoms in chips produced by different broaching teeth in the broaching process alternates with the cutting distance. In addition, the diffusion depth of hydrostatic pressure and von Mises stress increases significantly with the increase of broaching distance. The simulation results can provide atomic-scale details for the broaching process of single-crystal Ni Fe Cr alloys and help to optimize the nano-broaching process of nickel-based high-temperature alloys.