Adiabatic shear behavior of pearlitic heat-resistant steel under fragment-simulating projectile impact

Adiabatic shear band (ASB), as the precursor to catastrophic material failure, is of great significance in the research of impact resistance. This study investigated the adiabatic shear behavior of 12Cr1MoV steel under high-velocity impact from fragment-simulating projectile (FSP) using high-speed impact tests, numerical simulations, and scanning electron microscopy. The results demonstrated that the flat and wedge-shaped segments of the FSP experience different stress conditions and temperature fields during penetration. The asymmetry of the projectile has a pronounced effect on the morphology of the ASB. Two major failure modes were identified during the penetration process: tensile failure and shear failure, with pearlite exhibiting strengthening effects under both loading conditions. The ASB developed distinct microstructural characteristics with increasing impact velocity, exhibiting apparent sensitivity to temperatures and strain rates. Finally, the investigation of the ASB branches revealed the mechanisms underlying ASB formation and the initiation of catastrophic cracking. • The penetration mechanism was investigated under high-velocity FSP impact. • The mechanical response of pearlite under shear and tensile loading. • The varying FSP impact velocities influence ASB morphology. • The formation mechanism of ASB was investigated based on microstructural observation.