MICROSTRUCTURAL DEVELOPMENT OF ADIABATIC SHEAR BANDS FORMED BY BALLISTIC IMPACT IN A WELDALITE-049 ALLOY

The object of the present study is to investigate the microstructural development of the adiabatic shear band formed by ballistic impact in a WELDALITE 049 alloy. The microstructure of the shear band was examin ed by optical microscopy and transmission electron microscopy. The res ults indicated that the adiabatic shear band consisted of fine recryst allized grains with a high dislocation density. This microstructure wa s considered to be formed in an extremely short time by the combined e ffects of the highly localized shear deformation and the high-temperat ure rise that occurred within the shear band. However, no precipitates could be observed in the interior of the grains, since the temperatur e rise in the shear band formation process was inferred to be above 46 0 degrees C and below the solidus temperature. Dynamic recrystallizati on was suggested as a possible mechanism to explain the microstructura l development of the adiabatic shear band formed in the WELDALITE allo y.