Fu, X.; Zhang, F.; Zhu, W.; Pi, Z. Mechanical Properties and Toughening Mechanisms of Promising Zr-Y-Ta-O Composite Ceramics. Coatings2023, 13, 855.
Fu, X.; Zhang, F.; Zhu, W.; Pi, Z. Mechanical Properties and Toughening Mechanisms of Promising Zr-Y-Ta-O Composite Ceramics. Coatings 2023, 13, 855.
Fu, X.; Zhang, F.; Zhu, W.; Pi, Z. Mechanical Properties and Toughening Mechanisms of Promising Zr-Y-Ta-O Composite Ceramics. Coatings2023, 13, 855.
Fu, X.; Zhang, F.; Zhu, W.; Pi, Z. Mechanical Properties and Toughening Mechanisms of Promising Zr-Y-Ta-O Composite Ceramics. Coatings 2023, 13, 855.
Abstract
ZrO2-YO1.5-TaO2.5(ZYTO) composite ceramic is considered to be the candidate of next generation of thermal barrier coatings as its excellent thermal stability and low thermal conductivity in high temperature, however, the mechanical properties and fracture tougheness of ZYTO system may be the shortcomings compared with the 8YSZ. In this study, ZYTO composite ceramics were successfully prepared by chemical coprecipitation reaction, the microsture of resulting composites were studied as a function of doping of M-YTaO4. Mechanical properties, including the density, porosity, hardness and Young's modulus, are determinate; the toughening mechanism were verified by the crack growth behavior of Vickers indentation test Results suggested that M-YTaO4 refines the fluorite phase grain and strengthens the grain interface in the composite ceramic. The thermal mismatch between the second phase and matrix produces residual stress in the bulk and affects the crack propagation behavior. With the increase of M-YTaO4 doping, the grain coarsening and ferroelastic domains are observed in the experiments. The ferroelastic domains with orthogonal polarization directions near crack tip evidences the ferroelastic toughening mechanism. The competition among these crack behaviors, such as cracks deflection, bridging and bifurcation, dominates the actual fracture toughness of the composite. The best toughening formula is determinate in the two-phase region and the highest fracture toughness is about to 3.1MPa·m1/2. Above all, mechanical properties of ZYTO composite ceramics look potential for thermal barrier coatings materials.
Chemistry and Materials Science, Ceramics and Composites
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