Effects of the metal-ceramic transition region on the mechanical properties and crack propagation behavior of an Al2O3-40 wt% TiO2 coating
Autor: | Jianguo Lü, H. Luo, J. Feng, Jiansheng Lu, Asim Khan, Junjie Zang, X.P. Xiong, Peng Song |
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Rok vydání: | 2017 |
Předmět: |
Nial
Toughness Materials science Scanning electron microscope 02 engineering and technology engineering.material 01 natural sciences Coating 0103 physical sciences Ultimate tensile strength Materials Chemistry Ceramic Composite material computer.programming_language 010302 applied physics Metallurgy Fracture mechanics Surfaces and Interfaces General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Surfaces Coatings and Films visual_art visual_art.visual_art_medium engineering Deformation (engineering) 0210 nano-technology computer |
Zdroj: | Surface and Coatings Technology. 321:200-212 |
ISSN: | 0257-8972 |
Popis: | A modified coating system comprising a ceramic region, a metal-ceramic transition region (a region compounded with ceramic splats and NiAl splats) and a bond region is deposited by atmospheric plasma spraying (APS). The micro-structure and phase composition are studied using scanning electron microscopy and X-ray diffraction. The mechanical properties, stress distribution and crack propagation are evaluated with a bending test. At the same time, the thermal shocking resistance of the modified coating system (MAT40 coating system) is also estimated. The results show that the cracks are deflected by small NiAl splats and cross long NiAl splats after the large tensile deformation of the NiAl splats during bending test. In addition, the crack extends along the boundary of the columnar grain in the ceramic splats. The appearance of the transition region makes a toughness increase and stress gradient decrease. Net macro-cracks are observed at the surface of the Al2O3-40 wt% TiO2 coating with a conventional dual layer structure system. However, in the modified coating system, we find almost no cracks after the 50th cycle of thermal shocking. In addition, the intergranular cracks taken place in the coating both under continuous thermal shocking circles and three bend test. |
Databáze: | OpenAIRE |
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