Abstract
High temperature fatigue (R=0) damage and deformation behaviors of SUS304 steel thermally sprayed with Al_2O_3/NiCr coating were investigated using an electronic speckle pattern interferometry (ESPI) method. Surface cracks and delamination occurred after 1×(10)^5 cycles test when σ_<max> was 202Mpa at 873K. The lengths and number of cracks or delamination largely decreased when σ_<max> or temperature decreased to 115MPa or 573K, respectively. Strain values along cracks measured with the ESPI method were much larger than other areas due to crack opening under the tensile load. The positions of strain concentration zones on strain distribution figures by ESPI method were well corresponded to those of cracks on sprayed coatings. Strain values decreased largely where local delamination occurred.
