Rapidly solidified ferromagnetic shape memory alloys
“Politehnica” University of Timisoara, P-ta Victoriei No. 2, 300006 Timisoara, Romania
2 West University of Timisoara, Bd. V. Parvan No. 4, 300323 Timisoara, Romania
3 National Institute of Research and Development for Technical Physics, 47 Mangeron Boulevard, 70050 Iasi, Romania
4 National Institute of Materials Physics, PO Box MG 07, 77125 Bucharest Magurele, Romania
Ferromagnetic shape memory alloys have been manufactured by various techniques involving rapid solidification. Bulk alloys have been obtained by extracting the melted alloy in especially designed copper molds; glass coated wires have been obtained by drawing the melt from glass recipients followed by water cooling and ribbons have been fabricated by melt-spinning. Microstructural observations show particular solidification aspects of fractured areas, while ferromagnetic behavior has been detected in glass coated wires obtained by rapid solidification. The martensitic microstructure was observed on Co-Ni-Ga rapid solidified bulk alloys and Fe-Pd ribbons. The memory effect was detected using a Vibran system that allows the detection of the phase transition for the ribbons and by visual observation for other specimens. The conclusions of the observations are related to the comparison between the ferromagnetic behaviors of shape memory alloys solidified using different techniques.
© EDP Sciences, Springer-Verlag, 2008