J. Phys. IV France
Volume 110, September 2003
Page(s) 923 - 928

J. Phys. IV France
110 (2003) 923
DOI: 10.1051/jp4:20020812

Phase transformations in Ni 3AI, Ti 3AI and Ti 2AINb intermetallics under shock-wave loading

N.V. Kasantseva1, B.A. Greenberg1, A.A. Popov2 and E.V. Shorokhov2

1  Institute of Metal Physics, Ural Division, Russian Academy of Sciences, GSP-170, 18 S. Kovalevskaya Str., Ekaterinburg, Russia
2  Ural State Technical University, 3 Mira Str., Ekaterinburg, Russia

Phase transformations induced in Ni 3AI, Ti 3AI-based superalloy with an addition of niobium, and orthorhombic Ti 2AINb aluminides by shock-wave loading were studied. The samples were subject to an impact of a steel plate. The maximum pressure on the surface of the samples was 100 GPa. The loading pulse was 1  $\mu$s. It was shown that the Ll $_2\rightarrow DO_{22}$ phase transformation took place in a single crystal of the superalloy containing 90% Ni 3AI intermetallic phase. A banded structure passing through initial $\gamma'$-cuboids and regions with twins, which were the DO 22-phase, were detected. The B $_2\rightarrow DO_{19}$ phase transformation was revealed in the polycrystalline Ti-25.6 at. % Al-10.3 at. % Nb alloy after shock loading. Long straight dislocations, which occasionally formed slip bands, were located in grains of the DO 19 phase and fine particles of the B 2 phase were present instead of interlayers. Fine particles of the B 19 phase, which was disordered on niobium, were found in the polycrystalline orthorhombic Ti-25 at. % Al-22 at. % Nb alloy after loading. The particles were observed along boundaries of initial plates of the orthorhombic O-phase. These observations were compared with results obtained after quasistatic compressionshear loading and cold or hot rolling.

© EDP Sciences 2003