Surface deformation micromechanics of erosion damage at different angles and velocities for aero-engine hot-end components

Abstract

Wrought superalloy materials have been extensively used to manufacture hot-end components of small-scaled aero-engines. During take-off and flying at low altitude, airplane components such as turbine disks are subjected to ultrahigh speed erosion by low-flux, small-grained sand particles, which renders their service life shorter than the expected design life. Therefore, it is urgent to clarify the damage mechanism of wrought superalloys subjected to solid-particle erosion. In the present study, we have manufactured three types of wrought superalloys by using a dual process combining vacuum induction and electro-slag remelting, followed by solution aging treatments. The fabricated alloys are designated as GH720Li, GH4738, and GH4169. Solid-particle erosion tests are performed using 700 µm silica sand particles, at impact angles between 30° and 90° and particle velocities of 25 and 55 m/s. Simultaneously, using the experimental parameters, a multi-particle dynamic model of erosive wear is established using the ANSYS LS-DYNA software. To analyze the elastoplastic behaviors of the target surfaces under the combined effect of impact particles velocities and angles, the damage mechanism of multiple particles simultaneously impacting on the surface of target materials is developed using a non-linear material model. Additionally, the microstructures and microhardness of the alloys are analyzed to study the erosion-related properties of the eroded subsurface after erosion tests. The erosion results show that the three alloys exhibit different degree of wear removal under the joint effect of the impact velocity and angle, including high velocity/low angle, high velocity/high angle, low velocity/high angle, and low velocity/low angle conditions. Analysis of the erosion-related properties indicates that the microstructural changes and variation in the microhardness of the subsurfaces after the erosion tests prevent deterioration of the substrate due to erosion damage. The multi-particle simultaneously impacting model reveals the correlation mechanisms between the erosion failure properties of various material surfaces under different conditions and the elastoplastic behavior of the subsurface. These results would contribute to the improvement of the service life of the turbine disk components under erosion failure and provide a theoretical basis for their structural design.