Autori: Bogdan Pricop, Umut Söyler, Burak Özkal, Nicoleta Monica Lohan, Adrian Liviu Paraschiv, Marius-Gabriel SURU and Leandru-Gheorghe Bujoreanu
Editorial: Materials Science Forum, Vols. 738-739, p.237-241, 2013.
Fe-14 Mn-6 Si-9 Cr-5 Ni (mass. %) shape memory alloys (SMAs) were produced from
raw powders employed both in initial commercial state and in a mixture state of equal fractions of
commercial and mechanically alloyed (MA’d) particles. After blending, pressing and sintering,
powder compacts were hot rolled (HR’d) and solution treated (ST’d) before being machined into
plane-parallel lamellas. Specimens with special geometry were pre-strained on a tensile testing
machine. By means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) the
presence of ε hexagonal close packed and α’ body center cubic stress induced martensites was
revealed and their thermally induced reversion to γ face center cubic austenite was evaluated by
modulated differential scanning calorimetry (MDSC). The results enabled the study of the influence
of MA, HR, ST and pre-straining on phase structure and associated on shape memory effect (SME).
The lamellas were hot formed into rings, which were trained in bending. Diameter reduction of
trained enlarged rings, on heating, was monitored by cinematographic analysis.
Cuvinte cheie: Fe-Mn-Si-Cr-Ni shape memory alloy, powder metallurgy, mechanical alloying, stress induced martensite