Gas‐gun reverse‐ballistic impact deformation and fracture of Armco iron Taylor specimens of differing grain sizes

Taylor cylinder specimens of Armco iron have been prepared with average grain sizes of 20 and 91 microns. For each grain size, impacts were performed at 193 and 295 ms−1. The extent of fracturing that occurred at the specimen peripheries was only minor at the lower velocity but was pronounced at the greater velocity. Radial striations of softened or melted material were observed on the specimen and anvil disk impact surfaces. EPIC‐2 predictions using the Zerilli‐Armstrong constitutive equation are compared to the measured specimen outlines and to the extent of deformation twinning observed in metallographic examination of specimen longitudinal sections.