Effect of Interlayer on the Residual Stresses within High-Temperature Coating

2006 ◽  
Vol 514-516 ◽  
pp. 1318-1322
Author(s):  
Xian Cheng Zhang ◽  
Bin Shi Xu ◽  
Hai Dou Wang ◽  
Yi Xiong Wu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Residual Stresses ◽  
Thermal Cycling ◽  
Physical Meaning ◽  
Thermal Barrier ◽  
The Finite Element Method ◽  
Material Combination ◽  
Barrier Coating

The effect of NiCoCrAlYx-ZrO2 (1-x) interlayer on the residual stresses in the ZrO2/NiCoCrAlY thermal barrier coating due to thermal cycling was analyzed using the finite element method. Modeling results showed that the magnitude and distribution of the residual stresses in the coating were strongly influenced by the material combination characterized by the value of x and the thickness of interlayer. The maximum tensile stresses at the different regions (i.e. coating/substrate interface, coating surface, et al.) as functions of the material combination and the thickness of the interlayer were obtained. The physical meaning of the above results was also discussed.

Investigation about Thermal Shock Property of Plasma-Spraying Sm2Zr2O7 Thermal Barrier Coatings with Different Substrate Condictions

2011 ◽  
Vol 354-355 ◽  
pp. 145-148
Author(s):  
Hong Song Zhang ◽  
Hong Chan Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Expansion ◽  
Residual Stresses ◽  
Plasma Spraying ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Shear Stresses ◽  
Substrate Thickness ◽  
Barrier Coatings

Effect of substrate conditions, including material type, thickness and radius of substrate, on thermal-shocking stresses of plasma spraying Sm2Zr2O7/ NiCrCoAlY TBCs was analyzed through finite element method. Results show that radial stresses decrease with time increasing, and they decrease with the increasing of distance from center to edge along radius. However, axial residual stresses increse abruptly at the edge of specimen. All residual stresses increse with incresing of thermal expansion coefficient of substrate. Radial stresses increase with substrate thickness increasing, however, they are not effectd by substrate thickness if it is great than 20mm.and axial residual stresses and shear stresses are not effected by the substrate thickness. The maximum values of axial stresses and shear stresses were not effected by sustrate radius. and values of radial stresses remian invariable when substrate radius is over 18mm.

An Ultrasonic Knife System for MEMS Packaging

2012 ◽  
Vol 190-191 ◽  
pp. 23-27
Author(s):  
Jin Sha ◽  
Zhi Yuan Yao ◽  
Yang Jiao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
High Frequency ◽  
Ultrasonic Transducer ◽  
The Finite Element Method ◽  
Structure Amplitude ◽  
High Frequency Vibration ◽  
Mems Packaging ◽  
The Impact

This paper proposes an ultrasonic knife system for MEMS packaging. The ultrasonic knife system is consisted of an ultrasonic transducer, a cutter and a gripper feeder. The ultrasonic transducer engenders high frequency vibration, which lead to the resonance of the structure. Amplitude transformer can magnify the amplitude. By the impact and collision of the cutter, the material can be cut through, and the high temperature created by high-frequency vibration can do the welding. The structure is designed and optimized by the finite element method, and a model machine is produced. According to the experimental results, the ultrasonic knife system has the virtues of high cutting force and better wedding feature, which are suitable for MEMS packaging.

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