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폴리타이포이드 경사 방식으로 접합 된 이종 세라믹간의 적층 수의 최적화 및 잔류응력 해석에 대한 연구

Title
폴리타이포이드 경사 방식으로 접합 된 이종 세라믹간의 적층 수의 최적화 및 잔류응력 해석에 대한 연구
Other Titles
Optimization of Crack-Free Polytypoidally Joined Dissimilar Ceramics of Functionally Graded Material (FGM) Using 3-Dimensional Modeling
Author
이선영
Keywords
Si3N4-Al2O3 joining; ,functionally graded material; polytypoid; finite element method
Issue Date
2008-10
Publisher
한국재료학회
Citation
한국재료학회지, v. 18, No. 10, Page. 547-551
Abstract
Crack-free joining of Si3N4 and Al2O3 using 15 layers has been achieved by a unique approach introducing Sialon polytypoids as a functionally graded materials (FGMs) bonding layer. In the past, hot press sintering of multilayered FGMs with 20 layers of thickness 500μm each has been fabricated successfully. In this study, the number of layers for FGM was reduced to 15 layers from 20 layers for optimization. For fabrication, model was hot pressed at 38 MPa while heating up to 1700˚, and it was cooled at 2˚/min to minimize residual stress during sintering. Initially, FGM with 15 layers had cracks near 90 wt.% 12H / 10 wt.% Al2O3 and 90 wt.% 12H/10 wt.% Si3N4 layers. To solve this problem, FEM (finite element method) program based on the maximum tensile stress theory was applied to design optimized FGM layers of crack free joint. The sample is 3-dimensional cylindrical shape where this has been transformed to 2-dimensional axisymmetric mode. Based on the simulation, crack-free FGM sample was obtained by designing axial, hoop and radial stresses less than tensile strength values across all the layers of FGM. Therefore, we were able to predict and prevent the damage by calculating its thermal stress using its elastic modulus and coefficient of thermal expansion. Such analyses are especially useful for FGM samples where the residual stresses are very difficult to measure experimentally.
URI
http://db.koreascholar.com/Article?code=296897https://repository.hanyang.ac.kr/handle/20.500.11754/104992
ISSN
2287-7258
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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