Fatigue Behaviour of a Short Crack in a Thin Protective Layer Laser-cladded on a Steel Substrate

Abstract

Fatigue behaviour of a short crack in a thin protective laser-cladded laye r has been investigated. A two-dimensional finite element model of a steel bar with two thin cracked layers on its both sides was created. Propagation of a crack under pure tension and pure bending was studied via linear elastic fracture mechanics concept considering various Young’s modulus of the surface layers. The effect of the elastic mismatch between both materials is demonstrated considering the critical stress intensity factor range of 20 to 25 MPa·m1/2 as it is typical for aluminium alloys. It is shown that more compliant materials enhance the critical crack length that causes the unstable crack growth and therefore also the lifetime of the component with laser-cladded protective layers.