The efficiency of gas turbines is closely associated with sealing systems between rotor and stator. Most widely used are labyrinth seals with honeycomb liners, which allow for minimum leakage and tolerate rub events. In order to avoid a severe damage of rotor, the wear during rub-in should only occur on the honeycomb side. For the prediction of rub-in effect, it is important to understand the microstructural changes and the wear mechanisms at high strain rates and high temperatures. However complex stress, strain and temperature loadings in jet engines hinder the analysis of the main influencing parameters on wear of honeycomb seals.
Therefore tensile tests with various strain rates (from 1,25 to 50 1/s) were performed from room temperature to close to the melting point on thin sheets by means of a servo-hydraulic test machine Gleeble 3500. The correlation between the mechanical properties and the dislocation structures in the solid solution hardened Hastelloy X and in the precipitation hardened Haynes 214 nickel-based superalloys are derived. Furthermore, the microstructures of samples tested in a rub-in test rig and samples from out of service honeycomb liners are investigated. Dislocation analysis is carried out using EBSD and ECCI on a FEI Apreo. Based on these experimental data a multiscale finite element model for rub-in events in order to predict wear of honeycomb seals is anticipated.