Twinning properties of lattice planes

Abstract

A novel crystallographic analysis is undertaken of atomic movements in deformation twinning of metals.Body-centred cubic metals, indium and mercury are treated in detail, and it is established that the operative twinning mode always involves the smallest possible homogeneous shear which could twin the lattice.An analogous criterion is developed for multiple lattices.* There exists a fifth possibility, namely that 0a, 0b coalesce into a single plane, thus enabling an ideal twin to be produced.An analysis based on this possibility would be identical with that based on (3).* These are the indices of the operative mode when the fl-tin crystal is referred to a face-centred tetragonal unit cell.This choice of cell facilitates comparison with indium.