TiNi合金フラッシュ蒸着膜の柔軟性へ及ぼす成膜温度および熱処理の影響

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This paper focused on the effects of deposition temperature and annealing conditions on the flexibility and phase transformation behavior of thick (up to 10μm) flash-evaporated film of TiNi shape memory alloy (SMA). The TiNi films were characterized by differential scanning calorimetry (DSC), bending tests, and bulge tests. The phase transformation temperatures of the TiNi alloy film were little influenced by the deposition temperature, in the range of 250°C to 450°C. However, the phase transition peak became larger when the deposition temperature was 300°C or higher. The flexibility of the TiNi film was also improved drastically as the deposition temperature rose up. A flexible TiNi film, without fracture at a maximum strain of 1.5%, was obtained when the deposition temperature was 400°C or higher. The annealing temperature for shape memorization was optimum at 500°C. When the TiNi film was annealed at lower temperature (400°C), the TiNi film was not flexible. On the other hand, the phase transition peak became broad with annealing at a higher temperature (600°C). The TiNi film, deposited at 450°C and annealed at 500°C for 3h, could deform to at least a 4.5% strain in the bulge test. A residual strain of about 2% was obtained after the external load was released. When the TiNi film was heated above the phase transformation temperature, typical shape recover behavior was observed.
社団法人表面技術協会の論文
2008-09-01