Sputter-Deposited TiZrNi High-Temperature Shape-Memory Thin Films

摘要

Ti_(35.7)Zr_(14.9)Ni_(49.4), Ti_(35.0)Zr_(15.4)Ni_(49.7), and Ti_(33.4)Zr_(14.8)Ni_(51.7) thin films were prepared using a carousel type magnetron sputtering apparatus. The films were annealed at 973K, 873K, and 773K for 1 hour in order to produce crystallization. The films with Ni-poor compositions have fine microstructures with a sub-micron order grain size and contain ternary TiZrNi (λ_1) precipitates with a MgZn_2-type structure. The mechanical properties of the films were drastically improved, and the high temperature shape memory effects under tensile stress were realized. The Ti_(35.0)Zr_(15.4)Ni_(49.7) film annealed at 773K exhibits a nearly perfect shape memory effect even at 600MPa.