Ti-Ni-Zr高成形性形状記憶合金のマイクロ成形加工

抄録

Micro forming method of Ti-Ni-Zr high formable shape memory alloys (HFSMAs) using viscous flow in supercooled liquid region (SCLR) was investigated. Planer Ti₃₈Ni₅₀Zr₁₂ (at.%) samples were prepared by r.f. magnetron sputtering and were thin film metallic glasses (TFMGs). Glass transition temperature (T_g) and crystallization start temperature (T_x) were 704 and 764 K, respectively. SCLR (=T_x -T_g) was 60 K. Planer specimens were deformed and fixed using micro jigs. When they were heated to around the SCLR, the stress relaxation occurred by their viscous flow. We investigated heating conditions to stress-relax completely. Finally, we successfully obtained waved Ti₃₈Ni₅₀Zr₁₂ TFMGs in room temperature. The waved Ti₃₈Ni₅₀Zr₁₂ TFMG samples were annealed at 873, 973, 1073 K for 1 hour in order to crystallize and become waved SMAs. Martensitic transformation start temperature and the reverse martensitic transformation start temperature also increased with increasing the annealing temperature. These SMA samples exhibited a shape memory effect and/or superelasticity.