Study on Stress Development in the Phase Transition Layer of Thermal Barrier Coatings

Yijun Chai; Chen Lin; Xian Wang; Yueming Li

doi:10.3390/ma9090773

Study on Stress Development in the Phase Transition Layer of Thermal Barrier Coatings

Materials (Basel). 2016 Sep 13;9(9):773. doi: 10.3390/ma9090773.

Authors

Yijun Chai¹, Chen Lin², Xian Wang³, Yueming Li⁴

Affiliations

¹ State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Key Laboratory of Environment and Controlfor Flight Vehicle, Xi'an Jiaotong University, Xi'an 710049, China. cyj1991@stu.xjtu.edu.cn.
² State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an 710049, China. linchen19870117@stu.xjtu.edu.cn.
³ State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Key Laboratory of Environment and Controlfor Flight Vehicle, Xi'an Jiaotong University, Xi'an 710049, China. wangxian@mail.xjtu.edu.cn.
⁴ State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Key Laboratory of Environment and Controlfor Flight Vehicle, Xi'an Jiaotong University, Xi'an 710049, China. liyueming@mail.xjtu.edu.cn.

Abstract

Stress development is one of the significant factors leading to the failure of thermal barrier coating (TBC) systems. In this work, stress development in the two phase mixed zone named phase transition layer (PTL), which grows between the thermally grown oxide (TGO) and the bond coat (BC), is investigated by using two different homogenization models. A constitutive equation of the PTL based on the Reuss model is proposed to study the stresses in the PTL. The stresses computed with the proposed constitutive equation are compared with those obtained with Voigt model-based equation in detail. The stresses based on the Voigt model are slightly higher than those based on the Reuss model. Finally, a further study is carried out to explore the influence of phase transition proportions on the stress difference caused by homogenization models. Results show that the stress difference becomes more evident with the increase of the PTL thickness ratio in the TGO.

Keywords: constitutive equation; phase transition layer; stress development; thermal barrier coatings (TBCs).