FORMATION OF AMORPHOUS NICKEL ALUMINIDES UNDER SHOCK-WAVE LOADING

Recently we reported the synthesis of nickel aluminides from a mixture of elemental aluminum and nickel powders under explosive shock-wave loading. In this report we present the observation of an amorphous phase in the low-temperature region of the compacted sample where reactions of the elemental powders were sparse and localized. We report electron microscope observations of beginning compound formation in a mixture of Ni and Al powders under shock-wave loading. Key findings are an amorphous phase, the precipitation of NiAl from the same matrix, and a lamellar and a 'tweed' microstructure. For transmission electron microscopy thin sections of the designated region of the shock-loaded compact were made, mechanically polished and ion milled to electron transparency.