Study of phase transformations in Ni3Al superalloy after shock-wave loading

Phase transformations induced by pulsed shock-wave loading in a single crystal of the nickel superalloy have been studied. The crystal was loaded by an impact with a steel plate (the maximum pressure on the sample surface was 100 GPa, and the pulse duration was 10 mu s) and by the deceleration of explosion products at an obstacle (the maximum pressure was 20 GPa, and the pulse duration was 10 mu s). Depending on the loading conditions, various pressure-drop gradients behind the shock front were realized. After loading at 20 GPa, the crystal has a high dislocation density; after loading at 100 GPa, a banded structure with misorientation bands directed along the < 111 > directions is formed. X-ray diffraction, neutron diffraction, and high-resolution transmission electron microscopy of the crystal subjected to shock-wave loading reveal an L1(2) -> D0(22) phase transformation in it. Deformation microtwins are observed near microcracks in the D0(22) phase.