The Effect of Ti Content on alpha ' Martensite Phase Transformation, and Magnetic Properties by Mossbauer Spectroscopy in Fe-30%Ni-x%Ti (wt%) Alloys

Abstract

In this study, the influence of Ti content on the microstructure of the martensite bcc alpha'), which was formed by thermal effect, was investigated by scanning electron microscope and transmission electron microscope observations, kin Fe-30Ni-xTi (x = 0.8, 1.8, 2.6) alloys. The crystallographic orientation relationship between austenite fcc (gamma) and thermally induced bcc (alpha') martensite was found to be as (111)(gamma)//(011)(alpha) (Kurdjumov-Sachs (K-S)), by the electron diffraction analysis. The martensitic transformation temperature (M-s) of alpha' martensite was determined as -41 degrees C, -62 degrees C, and -76 degrees C in the alloys with 0.8%, 1.8%, and 2.6% Ti concentration, respectively. The Mossbauer spectrometer analysis has been revealed by a paramagnetic character for the austenite phase and magnetically order character for alpha' martensite phase. Hyperfine magnetic field, isomer shift and volume fractions of phases were determined by the Mossbauer spectroscopy.