Autori: A.-L. Paraschiv, F. Borza, N. Lupu, Marius-Gabriel SURU, N. M. Lohan, B. Pricop, I.-P. Spiridon, L.-G. Bujoreanu

Editorial: Journal of Optoelectronics and Advanced Materials, Vol. 15, No. 7-8, p.781 – 784, 2013.

Rezumat:

Two different types of Fe-base shape memory alloys (SMAs), obtained by different processing methods, were
comparatively analyzed from the point of view of: (i) structural characterization, (ii) morphologic aspects and (iii) mechanical
behaviour. For this purpose, heat treated specimens of Fe-9Cr-4Ni-0.33C and in Fe-28Ni-17Co-11.5 Al-2.5 Ta (mass. %)
were produced and prepared for X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations, which
enabled to detect the presence of α’ thermally induced martensite and γ austenite and to observed their respective
morphologies. By means of micro-indentation tests, the variations of load vs. depth were recorded and the presence of
pseudoelastic behaviour was confirmed, being ascribed to the presence of stable α’ martensite. When α’ martensite was
stress-induced from γ austenite, being unstable upon unloading, a superelastic response was obtained, as was the case for
Fe-28Ni-17Co-11.5 Al-2.5 Ta alloy.

Cuvinte cheie: Martensite, XRD, SEM, Micro-indentation, Pseudoelasticity, Reversible stress-induced transformation

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