The physical mechanism of the training process of TWSME has been studied in a Ni-49.7at%Ti alloy

by utilizing the measurements of electric resistance change

internal friction

elastic modulus and distortion strain for the fully trained specimen as well as un-trained specimen. It has been verified that a complete two way shape memory effect obtained through training process was provided by the I/C (incommensurate/commensurate) phase transformation in this alloy. The changes of electric resistance and resistant force of transformation have been studied and the essence of the training process is discussed. The substantive point of the training process is that under combined action of temperature and stress field

the I/C transformation is induced

the transformation resistant force tends to decrease and stabilize

making the transformation process reversible completely in a specific way. The specimen then possesses the two way shape memory effect.