Degree Name

Master of Engineering (Hons.)


Department of Materials Engineering


This thesis reports the influence of carbon addition on the s martensitic transfometion and shape memory effect (SME) in Fe-Mn-Si based alloys. At first, a critical review is given on the development, characteristics and the mechanism of shape memory in Fe-Mn-Si based alloys. Various effects on the alloys, such as annealing temperature, prestrain and deformation temperature, thermal and thermomechanical cycling on the e martensitic transformation and the SME are discussed. It is concluded that a high strength matrix and a low stacking fault energy are the essential conditions required to obtain a good shape memory effect for the Fe-Mn-Si base alloys. The experimental work was carried out in two parts. In the first part, the effects of different carbon levels on the 6 martensitic transformation temperatures and 8 martensite morphology in Fe-20Mn-6Si alloys were examined by means of differential scanning calorimetry and optical microscopy. It was found that carbon strongly decreased the 'y->e martensitic transformation temperature, Ms. The addition of 0.3wt% carbon was found to reduce the Ms tenperature by up to 120K. The phase transformation hysteresis (As-Ms) increased with increasing the carbon content. On the other hand, the 8 martensite plates or bands became thinner as the carbon content increased.



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.