Vibration Damping of Thermal Barrier Coatings Containing Ductile Metallic Layers

Abstract

This paper explores the vibration damping properties of thermal barrier coatings (TBCs) containing thin plastically deformable metallic layers embedded in an elastic ceramic matrix. We develop an elastic-plastic dynamical model to study how work hardening, yield strain, and elastic modulus o f the metal affect the macroscopic damping behavior of the coating. Finite element (FE) simulations validate the model and are used to estimate the damping capacity under axial and flexural vibration conditions. The model also pro vides an explanation for the widely observed nonlinear variation of the loss factor with strain in plasma-spayed TBCs. Furthermore, it facilitates the identification of multilayer configurations that maximize energy dissipation.

Damping performance of YSZ coating prepared by different EB-PVD parameters

“…These microscopic defects under alternating stress had the character of opening and contraction, which could lead to the damping characteristics. In order to analyse the effect of microscopic defects on the damping performance of the coating, Casadei et al [12] calculated the cantilever beams coated by YSZ_TBC in different vibration modes, and pointed out that the rearrangement of point defects under pressure is important for the damping performance. Patsias et al [13] studied the damping properties and elasticity of YSZ coatings prepared by both APS and EB-PVD methods.…”

“…In order to analyse the effect of microscopic defects on the damping performance of the coating, Casadei et al. [12] calculated the cantilever beams coated by YSZ_TBC in different vibration modes, and pointed out that the rearrangement of point defects under pressure is important for the damping performance. Patsias et al.…”

Damping Behavior of Layered Aluminium and Aluminide Coatings on AISI 316 Austenitic Steel

“…Specimen F: a polycrystalline intermetallic structure made of NiAl, FeAl plus an outer alumina layer. It must be pointed out that, as expected, intermetallic layers which have a comparable elastic modulus do not produce a relevant damping effect [8]. The result is a moderate increased damping A last group of specimens is made up of those annealed in an oxidative atmosphere: specimens C and F, which have the following configurations: specimen C, starting from the steel interface: a fractured Fe 2 Al 5 layer, followed by an Al-Si alloy layer and an outer alumina layer, Figure 1b.…”

“…Specimen F: a polycrystalline intermetallic structure made of NiAl, FeAl plus an outer alumina layer. It must be pointed out that, as expected, intermetallic layers which have a comparable elastic modulus do not produce a relevant damping effect [8]. The result is a moderate increased damping compared with similar configurations characterized by a low difference in CTE between layers of Fe-Al and NiAl or alumina, Figure 1f.…”

Experimental investigation of bi-modular material coating to enhance damping

“…Casadei et al [15] analyzed the vibration damping properties of thermal barrier coating containing the thin layer of ductile material incorporated in the elastic hard coating. For the analysis of required properties, a ceramic matrix (YSZ) inserted with thin layers of Platinum was developed.…”