An examination of twinning in α-neptunium

Abstract The twinning modes in α-phase neptunium have been re-examined using X-ray and transmission electron microscopy techniques. X-ray results confirm the predominant existence of {110} twinning as first reported by Rechtien et al. [8]. Transmission electron microscopy has additionally revealed {100}, {010} and possible {011} type twins in splat quenched samples. The crystallographic shear and atomic shuffles required for these additional modes are discussed relative to existing crystallographic theories of twinning.