HYPERPLASTICITY - ENHANCED FORMABILITY AT HIGH-RATES

Literature developed in the 1950's and 60's suggested that high formin g velocities can lead to improved ductility and formability. However f ew models exist that can predict the change in material formability an d it appears that this effect has rarely been put to use in practical metal forming. This report shows that very large increases in the form ability of three materials is observed in the electrohydraulic forming of a conical section and moderate increases are observed in the elect romagnetic expansion of aluminum rings. The ductility increase in the latter case is predicted well by a one dimensional finite element mode l.