Bending fracture behavior of freestanding (Gd0.9Yb0.1)2Zr2O7 coatings by using digital image correlation and FEM simulation with 3D geometrical reconstruction

Abstract

It is important to investigate the mechanical performances of (Gd 0.9 Yb 0.1 ) 2 Zr 2 O 7 (GYbZ) materials deposited on irregular substrates for improving new thermal barrier coatings. Three-point bending fracture characteristics of freestanding GYbZ coating prepared by supersonic plasma sprayed (SPS) technique were investigated with the help of digital image correlation technique. The cracking time, crack propagation path, and mechanical properties of GYbZ coating were obtained. Meanwhile, the X-ray computed tomography technique was introduced to scan the microstructure of freestanding GYbZ coatings, which are used to establish three-dimensional (3D) finite element model by using the Avizo software. The brittle cracking criterion was applied to describe the bending fracture process of GYbZ coatings. The critical cracking strain was estimated as 0.36%±0.03% by repeatedly comparing the difference between the experimental and simulated curves. The results would be extended to predict the dangerous region and failure mechanisms of GYbZ coatings deposited on irregular substrate during finite element simulations.

Composition Optimization, High-temperature Stability and Thermal Cycling Performance of Sc-doped Gd2Zr2O7 Thermal Barrier Coatings: Theoretical and Experimental Studies

“…When x=0.3125, it is an ideal pyrochlore structure, while when x=0.375, the system exhibits a disordered fluorite structure, that is, a larger value of xO-48f means a more disordered lattice structure [36]. After completing structural relaxation, the results of a0, xO-48f and density of the Gd2Zr2O7 model are obtained as shown in Table 1, which are 10.600 Å, 0.3386 and 6.79 g/cm 3 , respectively, showing agreement with the published values [37][38][39][40]. The above part demonstrates the reliability of our calculation results.…”

“…Thermal barrier coating (TBC) is a kind of high temperature protective coating used for aero turbine engine blades, prolonging blade working lifetime, improving thrust weight ratio and thermal efficiency [1][2][3]. TBCs are generally composed of a ceramic top coating, thermally grown oxide (TGO), bond coating and superalloy substrate.…”

Effects of surface roughness on CMAS corrosion behavior for thermal barrier coating applications

“…During aero engine operation, CMAS is deposited on TBC surface firstly, and then melts, wets, and infiltrates into the coating at high temperatures, which causes phase transformation of the coating and also mdestroys the coating microstructure, resulting in premature failure of TBCs [2,[13][14][15]. In the corrosion process of CMAS to TBCs, the wetting of molten CMAS plays an important role, which needs special attention and study.…”

Corrosion resistance of non-stoichiometric gadolinium zirconate fabricated by laser-enhanced chemical vapor deposition

“…Gadolinium zirconate (GZ) is a promising candidate of TBCs for the next-generation turbine engines [10][11][12][13]. The crystal structure of GZ can be described as a Zr 4 O 12 framework with an imbricated Gd 4 O 2 polyhedron inside [14][15][16]. Here, the Zr 4 O 12 framework provides high-temperature structural stability, and the Gd 4 O 2 polyhedron can scatter phonons and provide low thermal www.springer.com/journal/40145 conductivity [17,18].…”