Experimental study on two way shape memory effect training procedure for NiTiNOL shape memory alloy

This research describes training procedures for shape memory alloys (SMAs). SMAs are considered as a unique class of metal alloys that can recover apparent permanent strains when they are heated above a certain temperature. Shape Memory Effect (SME) is defined as the temperature driven response in SMA materials. The SME can be classified as either a One-way shape memory effect (OWSME) or a Two-way shape memory effect (TWSME). The TWSME response unfortunately requires repeated thermo-mechanical treatments known as "training" or "training cycles" before such a response is obtained. In this research work, the martensite deformation technique is used to train the SMA sample. Both the training procedure and the training jig was designed based on the bending mechanism procedure. The results obtained from the training process of SMA shows a great respond in SMA attack angle to their activation and de-activation temperatures. TWSME for SMA sample was successfully obtained in term of SMA sample attack angle value of 8° for SMA deactivation position and 39° for SMA activation position. Observations of spontaneous shape change as a result of the change in the sample temperatures were indications of the presence of TWSME in the SMA samples.