| Abstract: | Yb_3Al_5O_(12) has potential applications as thermal barrier coatings(TBCs) because it shows low thermal conductivity and close thermal expansion coefficient to nickel-based superalloys.As a prospective TBC material,besides superior thermal properties,the mechanical properties are also important.In this paper,we present the mechanical properties of Yb_3Al_5O_(12) including elastic moduli,hardness,strength,and fracture toughness.The Young's modulus of Yb_3Al_5O_(12) is 282 GPa.The shear-modulus-to-bulkmodulus ratio of Yb_3Al_5O_(12) is 0.63,which indicates relatively low shear deformation resistance.In addition,Yb_3Al_5O_(12) exhibits high strength and fracture toughness but low hardness compared to yttria stabilized zirconia(YSZ),the most successful TBC material.SEM observation reveals that the fracture surface of Yb_3Al_5O_(12) displays "layered structure feature",which is caused by crack deflection.Investigation based on Hertzian contact test demonstrates that Yb_3Al_5O_(12) is a damage-tolerant ceramic.Crack deflection and bridging can arouse shear faults,dissipate the local damage energy,and restrict the crack propagation within the material,which play an important role in enhancing the damage tolerance.The superior mechanical properties and good damage tolerance ensure Yb_3Al_5O_(12) a promising candidate for TBC applications. |
