Stress shielding in laser melting multilayered nickel-base superalloys under monotonic and cyclic loadings

In the present work, the mechanical properties and fatigue performance of laser melted mismatching nickel -base superalloys were investigated by multiscale experiments and computations. It confirmed that the local strength degradation does not affect the macroscopic stress-strain responses and overall low-cycle fatigue performance due to the stress shielding in the remelting material. The stress shielding mechanism was quantitatively illuminated and the critical shielding criterion was established. Accumulation of cyclic plastic deformations stimulates the cyclic stress softening and complete tensile mean stress relaxation in the remelting material, which significantly decreases the fatigue driving force of the mismatching material.