On the influence of strain-path changes on fracture

Abstract

Abrupt changes in strain path between uniaxial and equibiaxial tension are shown to have a large effect on plane-strain ductility. Data for titanium sheets, both with and without hydrides, show that a significant ductility enhancement occurs at a final strain state of plane-strain tension following multi-stage deformation sequences comprised of uniaxial and equibiaxial tension. While the dependence of ductile fracture on both accumulated damage and strain hardening suggests that failure strains should be sensitive to a nonproportional strain-path history, the detailed cause(s) of the present effect is not known.