Effects of thickness and elastic modulus on stress condition of fatigue-resistant coating under rolling contact

Abstract

The distribution and magnitude of surface and subsurface stresses of the single-layer sprayed-coatings on monolithic substrates were investigated by finite element method (FEM). The models of coating configurations with different thicknesses and elastic modulus ratios of coating to substrate were introduced, and the effects of thickness and elastic modulus ratio on the stresses were addressed. The calculation results show that the coating/substrate interface shear stress obviously decreases with increasing coating thickness, due to the location of the maximum shear stress moving away from the coating/substrate interface. At the same time, the magnitude of von Mises stress also declines in the case of thicker coatings. However, the high elastic modulus ratio results in extremely high maximum shear stress and the severe discontinuity of the von Mises stress curves, which leads to the intensive stress concentration on the coating/substrate interface. So the coating configurations with the larger coating thickness and lower difference of elastic modulus between coating and substrate exhibit excellent resistant performance of rolling contact fatigue (RCF).

Keywords

sprayed-coating / thickness / elastic modulus / maximum stress / von Mises stress / finite element method