Electron Beam-Physical Vapor Deposition (EB-PVD) is an effective technique for fabricating thermal barrier coatings (TBCs) with high strain tolerance. However, longitudinal growth of columnar grains generates grain boundaries parallel to the heat flow direction, forming low thermal resistance “heat flow channels” that increase thermal conductivity. This study analyzes temperature and stress fields in conventional T-type and zig-zag Z-type EB-PVD TBCs under thermal loading via the finite element method. Experimentally, both coatings were prepared and subjected to isothermal heat treatment at 1100 °C for 80 h. Compared with conventional coatings, zig-zag TBCs exhibited distinct thermal insulation, oxidation kinetics, interfacial fracture toughness, and elemental diffusion behaviors. Simulations and experiments confirmed that the zig-zag structure inhibited heat flow penetration, improved thermal insulation, slowed thermally grown oxide (TGO) growth, and mitigated interfacial fluctuation after aging. The interfacial fracture toughness of zig-zag coatings decreased from 3.35 MPa·m 1/2 (0 h) to 2.37 MPa·m 1/2 (80 h), 7.2% higher than that of conventional ones. An Al-Zr mixed area was observed near the TC/TGO interface, while Co and Cr diffusion was suppressed in zig-zag structures. These results verify that the zig-zag columnar structure enhances EB-PVD TBCs’ thermomechanical performance.
Liu et al. (Fri,) studied this question.
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