AbstractVoid nucleation at second-phase particles has been studied in round–notched, cylindrical tensile specimens of an ingot–cast AI–Li quaternary alloy. The volume fraction and distribution of voids has been determined as a function of strain history for samples in the solution–treated, peak–aged, and overaged conditions, and values of the stress to form cavitation calculated. The intermetallic phase responsible for void nucleation has been identified as being Fe–and Cu–rich; voids nucleate following the fracture of these particles. A mechanism of failure is proposed based on stress concentration at the particle/matrix interface where coplanar slip bands impinge.MST/78