Characterizations of martensite in Fe-30%Ni-3%Pd alloy

Abstract

Morphological, magnetic and thermal characteristics of thermally induced martensite in Fe-30% Ni-3% Pd (wt.%) alloy has been studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimeter (DSC), X-ray diffraction (XRD) method and Mössbauer spectroscopy. Kinetics of the transformation was found to be as athermal. Plate martensite morphology was observed during microscope observations. SEM and TEM observations and x-ray method revealed ?? (bcc) martensite formation with twinning. The crystallographic orientation relationship between the austenite and martensite exhibited a (110?) a? //(111?)? [111]?? //[110]? K-S type orientation relationship. The mean value of the lattice parameter of the austenite and martensite phase calculated as 3.5704 ? and 2.8614 ? respectively. In addition, the magnetic properties of both the austenite and martensite phases were determined by the Mössbauer spectroscopy. The Mössbauer spectra showed a paramagnetic character for the austenite phase and a ferromagnetic (or antiferromagnetic) character for the martensite phase. Also, Mössbauer studies shows that the value of hyperfine field increases with an addition of Pd element. © IDOSI Publications, 2014.