Effect of Aluminized Modified PS - PVD 7YSZ Thermal Barrier Coating on the Mechanical Properties of DZ125 Alloy

Abstract

Plasma spraying-physical vapor deposition(PS-PVD) process was applied to prepare aluminized modified thermal barrier coatings(TBCs) on the DZ125 superalloy substrate. In order to provide technical support for the application in service enviornments with complex mechanical loads, the fracture morphology and coating surface of DZ125 superalloy were observed by scanning electron microscope(SEM), and the effects of aluminized modified TBCs on DZ125 alloy in the aspects of tensile properties at room temperature, permanent tensile properties at high temperature and rotating bending fatigue properties at high temperature were investigated. Results showed that the tensile properties of the sample with aluminized modified TBCs at room temperature were equivalent to those of the matrix alloy, and the elongation after fracture increased slightly. Meanwhile, the tensile fracture was stepped cleavage plane, showing obvious brittle fracture characteristics. The high temperature persistent tensile fracture had the mixed characteristics of cleavage fracture and dimple fracture. And the plasticity of the persistent fracture was obviously improved, while the elongation after fracture was reduced. The rotating bending fatigue fracture consisted of three zones: fatigue origin zone, fatigue expansion zone and instantaneous fracture zone. The fatigue life of the coated sample was greatly improved compared with that of the matrix alloy.

Keywords

• dz125 superalloy| aluminized modified ps-pvd thermal barrier coating| mechanical properties| fracture morphology