Lianbo Wang

Sputter-deposited Ti–Ni–Cu shaped memory alloy thin films

Abstract Ti 50 NiCu 5 thin films were prepared by r.f. magnetron sputtering. The compositions were determined by electron probe microanalysis. The phase transformation characteristics were examined by resistivity measurements. The substrate-curvature measurements were applied to determine the residual stress of the films based on silicon substrates. Tensile residual stress induces a two-stage transformation: B 2 →orthorhombic→monoclinic; and lowers martensitic transformation temperatures, while compressive residual stress accelerates the one-stage transformation: B 2 →monoclinic; and results in a transformation without temperature hysteresis. The reason is analyzed.

Hard and Corrosion-Resistant Ni-xAl-yTi Nanocomposite Coatings for CNT/Al Composites

The ternary Ni-xAl-yTi (x, y in wt.%) nanocomposite protective coatings were electroplated on carbon nanotubes (CNT)/Al composite by the co-deposition of Al and Ti particles at several current densities. The dependences of microstructure, microhardness, residual stress, and corrosion resistance of the ternary nanocomposite coating on current density were investigated. The results showed that the embedded Al and Ti particles caused the crystallite refinement and the decrease of [200] fiber texture of nanocrystalline Ni matrix when current density decreased. The microstructure evolution endowed the ternary nanocomposite coating with high microhardness and corrosion resistance. The surface residual stress of the ternary nanocomposite coating increased with decreasing current density.