Materials Science Forum, Vol.475-479, 1965-1968, 2005
The effect of rapidly solidified microstructures on the martensitic transformation in Ti-50-Ni-45-CU5 shape memory alloys
Transformation behaviors and shape memory characteristics of Ti-N-45-Cu-5 alloy ribbons prepared by melt spinning were investigated by means of DSC, XRD and OM. In these experiments particular attention has been paid to change the ejection temperature of the melt from 1400 degrees C to 1600 degrees C. As the results, the thickness of ribbons could be controlled. An increase of the superheat of the melt leads to a reduced ribbon thickness and a refinement of grains. The microstructural refinement and the increased internal strains achieved by controlling the melt-spinning temperature decreased M, significantly. It was also found that two-step transformation (B2-B19-B19') occurred in the ribbons fabricated at higher melt-spinning temperatures than 1450 degrees C.
Keywords:shape memory alloys;melt spinning;rapid solidification;martensitic transformation temperature