Abstract:The deformed microstructure evolution of depleted uranium impacted by steel projectile at a velocity of 50 m/s was investigated by means of confocal laser scanning microscope, electron backscatter diffraction, transmission electron microscope and indenter technique. The experimental results showed that the spherical cap crater was formed in depleted uranium target impacted by steel projectile, and the diameter and depth of the impacted crater were 5.45 and 1.01 mm, respectively. From crater rim to deep matrix, four deformed zones were classified, including twin fragmentation zone, high density deformation twin zone, low density deformation twin zone and matrix zone. Twinning was considered as the dominant plastic deformation mechanism of depleted uranium subjected to impact loadings. Besides twinning, the dislocation slipping also played an important role to accommodate the plastic deformation. Finally, the deformed microstructure evolution of depleted uranium under high velocity impact was proposed.

Key words: depleted uranium; steel projectile; dynamic deformation; microstructure evolution; twinning