Abstract
A plasma-sprayed aluminum-silicon (AlSi)/polyester coating is applied in modern gas turbine engines as an abradable sealcoating to maintain tight clearances between the rotating blades and the static casing. While running the engine, the rotating blades “rub” with the abradable coating, which results in extreme strain rate (up to 106) dynamics and a high-temperature environment. Due to the difficulty of collecting direct measurements, predictive computational models are important for analyzing the deformation and failure of the abradable material, to help meet the design target of avoiding damage to the blade tip and maintaining high fuel efficiency. In this research, a microstructure-based finite element (FE) computational model was developed to capture the complex mechanical behavior of the AlSi/polyester microstructure. The model is based on a virtual representative-volume-element (RVE) of a metal-polymer microstructure, reconstructed from x-ray computed tomography. It models the plastic deformation of, and damage to, each AlSi and polyester constituents, as well as the failure at their interface. The model was calibrated and validated with uniaxial tension and compression experiments, conducted at two temperatures (298 K and 533 K) at an applied strain rate of 103-104s-1. The material exhibited strongly asymmetric tension-compression behavior and a sensitivity to temperature, which was well captured by the model. The model was further applied to investigate changes in mechanical behavior due to variations in constituents’ volume fractions, which provides guidance to the microstructural design of AlSi/polyester abradable materials. The model is expected to facilitate the development of improved abradable materials by bypassing the conventional trial-and-error approach and extensive testing requirements.
Original language | English |
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Article number | 110791 |
Journal | Materials and Design |
Volume | 219 |
DOIs | |
State | Published - Jul 2022 |
Funding
This research was sponsored by the Oak Ridge National Laboratory (ORNL), Energy and Transportation Science Division. ORNL is managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract DE-AC05 00OR22725. This work was funded by the HPC4materials program supported by U.S. Department of Energy Office of Fossil Energy in collaboration with Pratt & Whitney, a division of Raytheon Technologies Corporation. Computing support by the Compute and Data Environment for Science (CADES) at Oak Ridge National Laboratory is gratefully acknowledged. The experiments support by the Dynamic Mechanics of Materials Laboratory (DMML), Ohio State University (OSU) is gratefully acknowledged.
Keywords
- Abradable material
- AlSi/polyester microstructure
- Failure mechanism
- Finite element modeling