Production of TiNi amorphous/nanocrystalline wires with high strength and elastic modulus by severe cold drawing

The microstructure and properties of Ti–50.9 mol.% Ni wires after severe cold drawing were studied. X-ray diffractometry, transmission electron microscopy and electrical resistivity measurements revealed that the amorphous phase was dominant in the as-drawn wires. Young’s modulus depended strongly on the drawing reduction. The amorphous/nanocrystalline wires after 70% reduction exhibit high tensile strength (>2 GPa), a high Young’s modulus (71 GPa) and a large pseudoelastic recovery strain (∼3%). The recovery strain was further improved to 5.8% by aging at 573 K.