Abstract
Static configurations of stress-induced martensite and pretransition microstructures in Ni62.5A137.5 have been studied with conventional as well as high resolution electron microscopy using single crystal TEM specimens containing defect sites of extremely high stress intensity. From images of different regions around such defects it can be concluded that the austenite lattice develops transverse displacement modulations with increasing amplitude and correlation directly related to the {110} shear-plus-shuffle displacements required to form the martensite structures. Different steps in this transition sequence are presented and discussed.