Failure Mechanisms

· Void formation occurs under the maximum values of the tensile and shear stresses at the center of the sample.
· Nucleation of a void through fracture of a brittle inclusion is shown.
· The combined stress due to dislocation pile-up and the applied external stress causes inclusion fracture (or debonding at the inclusion interface if the required debonding stress is lower than the fracture stress).
· Once formed the voids can coalesce by local plastic deformation.

From: Courtney, "Mechanical Behavior of Materials," McGraw Hill (1990)