A Method of Locally Eliminating Superelasticity of Shape Memory Alloy Spring

A heat treatment system was constructed based on a silicon carbide rod in order to locally eliminate the superelasticity of Ti-Ni shape memory alloy spring. The effects of heat treatment temperature, holding time on the hardnesses and microstructure of different parts of spring samples were studied. The results show that the local heat treatment system can heat samples to the temperature above 700 ℃ in a short time, and the temperature fluctuation of the target was less than 5 ℃ at the same preset temperature. This method can effectively eliminate the superelasticity of the target even in a very short time and meanwhile keep the main body of the samples unaffected when the heat treatment temperature was above 700 ℃.