AISI 304Cu STEEL SUBJECTED TO SMALL CHARGE EXPLOSIONS:MICROSTRUCTURAL CHANGES WITH LIMITED OR NO MACRODEFORMATION

摘要

Microstructural variations induced on AISI 304Cu steel disks by explosions which do not causegross macro-deformation are illustrated. 50 and 100 g NSP explosive spherical charges andexplosive-to-target distances in the range from 6.5 to 81.5 cm were used to achieve peakpressures in the 160 to 0.5 Mpa range. Two alloy grain sizes (60 and 32 μm) were tested.Microstructural features were studied by XRD, OM, SEM and STM microscopy. Surface OMand SEM evidenced partial surface melting, zones with recrystallization phenomena, andintense mechanical twinning. Phenomena in the interior of the samples restricted to twins. Theycan be seen up to some distance from the explosion impinged surface and again for a smallerdistance around the reflecting surface. The maximum charge-to-target distance at which thephenomena disappear has been singled out for each charge and alloy grain size and related tothe critical resolved shear stress for twinning.