Crystal structure determination of a ternary Cu(In,Sn)2intermetallic phase by electron diffraction

Abstract

Small grains of an intermetallic phase with an approximate composition Cu(In,Sn)2were observed in a metal matrix composite obtained from powders of a Cu–Al–Ni shape-memory alloy and an In–Sn matrix alloy. Samples of this composite were prepared for transmission electron microscopy and the crystal structure of the intermetallic phase was carefully investigated by applying electron diffraction techniques (microdiffraction, convergent-beam electron diffraction and precession), based on the analysis of the symmetry and the relative positions of reflections in the zero- and high-order Laue zones. It was found that the intermetallic phase has a body-centred tetragonal unit cell with lattice parametersa= 0.70 (3) nm andc= 0.56 (2) nm. Its crystal symmetry can be described by theI4/mcm(No. 140) space group.