A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System

Yan Song; Weijie Wu; Feng Xie; Yilun Liu; Tiejun Wang

doi:10.1371/journal.pone.0169738

A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System

PLoS One. 2017 Jan 19;12(1):e0169738. doi: 10.1371/journal.pone.0169738. eCollection 2017.

Authors

Yan Song^{1

2}, Weijie Wu¹, Feng Xie³, Yilun Liu^{2

3}, Tiejun Wang^{2

3}

Affiliations

¹ School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China.
² State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China.
³ School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an, China.

Abstract

Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model. Afterwards, some important geometric parameters for DCL-TBCs, such as the thickness ratio of stabilized Zirconia (YSZ, ZrO2-8%Y2O3) layer to Lanthanum Zirconate (LZ, La2Zr2O7) layer, which is adjustable in a wide range in the fabrication process, have a remarkable effect on its performance, therefore, the effect of this thickness ratio on residual stress generation in the fabrication process of DCL-TBCs has been systematically studied. In addition, some thermal spray treatment, such as the pre-heating treatment, its effect on residual stress generation has also been studied in this work. It is found that, the final residual stress mainly comes from the cooling down process in the fabrication of DCL-TBCs. Increasing the pre-heating temperature can obviously decrease the magnitude of residual stresses in LZ layer, YSZ layer and substrate. With the increase of the thickness ratio of YSZ layer to LZ layer, magnitudes of residual stresses arisen in LZ layer and YSZ layer will increase while residual stress in substrate will decrease.

Grants and funding

National Nature Science Foundation of China (http://www.nsfc.gov.cn/, Grant No.: 11502190, YS), China Postdoctoral Science Foundation Funded Project (http://www.chinapostdoctor.org.cn/, Grant No.:2016M592780, YS), National Program on Key Basic Research Project (973 Program) (http://www.most.gov.cn/, Grant No.: 2013CB035701, TW. And 2015CB057602, GC, this funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.)