MARTENSITE TRANSFORMATIONS IN Fe-Pd ALLOYS

Martensite transformations in Fe-Pd alloys have been extensively studied by means of X-ray diffractometry, optical and electron microscopy and Mössbauer effect. Successive martensite transformations were found in the Fe-Pd alloys with about 30at% Pd. The first was a thermoelastic type transition from the fcc austenite to an fct martensite, and the second was of non-thermoelastic type from the fct martensite to a bct martensite. The shape memory effect was found in the alloys which exhibited the thermoelastic nature of the fcc to fct martensite transformation. The stress induced bct martensite was obtained in the alloys with Pd content higher than 30at%, which did not show thermally induced bct martensite. Only bcc martensite was observed in asquenched specimens of the alloys with Pd less than 27at%