A plate impact experiment is used to study dynamic ductile rupture at strain rates up to l0 s s-1 in a spheroidized 1045 steel. The material has a microstructure consisting of a fine dispersion of cementite particles embedded in ferrite particles. Plane strain tensile loading is generated by impacting a deeply notched specimen with a thin elastic flyer plate. The notch, parallel to the impact plane and extending halfway through the diameter, is filled with steel shims to transmit compressive stress waves. Upon reflection from the rear surface of the specimen, the waves become tensile in nature and cause an opening mode of loading at the blunt notch tip, resulting in ductile void nucleation and growth thereβ’ The nucleation of voids is observed to occur through particle matrix debonding, particle fracture and particle-particle separation. Extensive void growth is observed at the notch tip as the impact velocity is increased. Relative notch opening displacement is found to depend on the initial notch width as well as the impact velocity. At impact velocities above 0.14 mm//zs, void nucleation due to the reflected tensile waves is also observed away from the notch along a plane parallel to the rear surfaceβ’ This spallation is studied in one version of the plate impact experiment that does not involve a notch. Scanning electron microscopy of the rupture surfaces shows that spallation occurs mainly by cleavage of the ferrite grains and is assisted by void nucleation and growth on separate void sheets. Free surface velocities are monitored and analyzed at three points in front of the notch tip on the unnotched side by means of a normal velocity interferometer system. A dynamic finite element method based on a constitutive law proposed by Gurson for porous materials is used to simulate the experiments. The results have identified the mechanism for damage through the calculated and measured free surface velocity profiles.