High resolution transmission electron microscopy study of nanoscale Ni-rich NiAl films evaporated onto NaCl and KCl

The atomic and microstructure of Ni-rich B2 NixAl100-x thin films with nanoscale dimensions, for thickness as well as lateral grain size, and produced by evaporation onto NaCl and KCl(001) surfaces are investigated by high resolution electron microscopy. Different textures and orientation relationships with the substrate are found exhibiting grains with [001],[011] and [111] zones parallel with the film normal. Local distortions including precursor-like domains and surface shearing as well as dislocations are observed in the grains. No micromodulations as in bulk martensite precursors are visible. No martensitic transformation was observed when cooling the free standing films to -170°C.