Effects of Annealing and Training on NiTi Alloy Ring for Clamping Device

Abstract

Shape memory alloys (SMAs) in the form of rings or tubes with two-way shape memory effect (TWSME) have been applied to high-speed precision micro-mechanical systems. This study investigates the development of NiTi alloy rings with TWSME and analyzes the effects of annealing and thermo-mechanical treatments. The results show there is a maximum in TWSME with respect to annealing temperature, loading deformation, training temperature, and cycle, respectively. The TWSME of SMA rings stabilizes earlier than structure dimension during training. The annealing and training change phase transition temperatures, which has a negative effect on the SMA ring with application to clamping device. A prototype ring made of Ni-49.2 at%Ti was developed and applied to a high-seed precision micro-spindle. Its performance under static and ultra-high speed rotation conditions was tested. The results show the ring developed in this study satisfies the operation and clamping requirements of high-speed precision micro-mechanical systems.

Keywords:

• Annealing
• Clamping
• Force
• Memory
• Micro-spindle
• Niti
• Ring
• Shape
• Training
• Two-way