0
TECHNICAL PAPERS

A Study of Thermal Fracture in Functionally Graded Thermal Barrier Coatings Using a Cohesive Zone Model

[+] Author and Article Information
Sudarshan Rangaraj, Klod Kokini

School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-1288

J. Eng. Mater. Technol 126(1), 103-115 (Jan 22, 2004) (13 pages) doi:10.1115/1.1631028 History: Received November 01, 2002; Revised April 01, 2003; Online January 22, 2004
Copyright © 2004 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Schematic illustration of the architecture of functionally graded thermal barrier coatings with similar thermal resistance (all dimensions in millimeters, figure NOT drawn to scale): (a) one-layer TBC; (b) three-layer TBC; and (c) nine-layer TBC, each TBC layer and bond coat are 0.22 mm thick.
Grahic Jump Location
Effective traction (σ)-separation (δ) curve for YSZ-BC alloy particulate composite (50 percent YSZ+50 percent BC alloy). S.C.M.-self-consistent model, R.O.M.-rule of mixtures
Grahic Jump Location
Schematic illustration of the thermal/structural boundary conditions during the laser thermal shock experiment and resulting fracture in the TBC
Grahic Jump Location
Finite element mesh for the three-layer TBC with two surface cracks in the symmetric model
Grahic Jump Location
Deformed shape (displacements magnified 10X) of the mesh in the region around the center and side surface cracks at various instances during the 4 seconds heating-ambient cooling (10 sec) thermal shock cycle with maximum surface temperature of 1100°C
Grahic Jump Location
Surface thermal fracture in the one-layer (non-graded) YSZ TBC. (Open symbols denote experimental data, details related to the cohesive parameters and crack-tip location criteria used for the above six cases are shown in Table 3.)
Grahic Jump Location
Surface crack (SC) morphologies resulting from laser thermal shock in the three-layer TBC, SC1-longest surface crack, SC3-shortest surface crack and SC2-surface crack of intermediate length: (a) micrograph of a three-layer specimen subjected to laser thermal shock with maximum surface temperature of 1000°C; and (b) schematic illustration of surface cracks typically observed on the three-layer TBC.
Grahic Jump Location
Surface thermal fracture data for the graded three-layer TBC. (Open symbols denote experimental data, Average (* ) denotes average of the longest two surface cracks (SC1 and SC2) measured on the tested specimens, SCM-self consistent model, ROM-rule of mixtures, F.E. model-finite element model.)
Grahic Jump Location
Work of separation (fracture toughness) for YSZ-BC alloy composites estimated from the self-consistent model, ΓC-YSZ=0.15 J/m2
Grahic Jump Location
Comparison of the surface crack lengths predicted from the finite element (F.E.) model with those measured from laser thermal shock experiments (10 specimens) for the nine-layer functionally graded TBC.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In