Abstract
In order to characterize the cracking patterns observed in thermally-sprayed WC-Co cermet and Al2O3-TiO2 ceramic coatings under nonuniform two-dimensional stress, the hydraulic bulge test of a coated disk specimen with a hole and the punch press test of a disk specimen without a hole were conducted. The observed cracking patterns on the coatings changed in the radial direction depending on the relative strength of coating to interface and the stress distribution. The appearance of the cracking patterns was explained well by “FEM Analysis-Strain Combination Method” which accommodates the strain of substrate with coating from elastic-plastic analysis and the strain of substrate from finite element method. Moreover, the calculated sizes of cracks agreed well with those measured in experiments.
