A TRANSMISSION ELECTRON-MICROSCOPY STUDY OF THE MICROTWINS FORMED DURING THE CRYSTALLIZATION OF AN AMORPHOUS NIZR2 ALLOY

Abstract The crystallization characteristics of an amorphous NiZr2 alloy have been studied by transmission electron microscopy. Striations in NiZr2 crystallites were found to be narrow twin bands, sometimes only a few layers thick, with 〈110〉 as the twin axes and a rotation of ±120°. High-resolution lattice images prove the composition plane to be the {110} planes perpendicular to the 〈110〉 twin axes. This twin relationship can be accounted for by the existence of a hexagonal cluster of Ni and Zr atoms parallel to {110} within the body-centred tetragonal unit cell of NiZr2.