Autori: B. Pricop, U. So¨ yler, N.M. Lohan, B. O¨ zkal, L.G. Bujoreanu, D. Chicet, and C. Munteanu

Editorial: Springer, Journal of Materials Engineering and Performance, 21(11) DOI: 10.1007/s11665-012-0168-5, p.2407-2016, 2012.

Rezumat:

In order to produce shape memory rings for constrained-recovery pipe couplings, from Fe-14 Mn-6 Si-9
Cr-5 Ni (mass%) powders, the main technological steps were (i) mechanical alloying, (ii) sintering, (iii) hot
rolling, (iv) hot-shape setting, and (v) thermomechanical training. The article generally describes, within its
experimental-procedure section, the last four technological steps of this process the primary purpose of
which has been to accurately control both chemical composition and the grain size of shape memory rings.
Details of the results obtained in the first technological step, on raw powders employed both in an initial
commercial state and in a mixture state of commercial and mechanically alloyed (MA) powders, which were
subjected to several heating-cooling cycles have been reported and discussed. By means of differential
scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD), the
thermal behaviors of the two sample powders have been analyzed. The effects of the heating-cooling cycles,
on raw commercial powders and on 50% MA powders, respectively, were argued from the point of view of
specific temperatures and heat variations, of elemental diffusion after thermal cycling and of crystallographic
parameters, determined by DSC, SEM, and XRD, respectively.

Cuvinte cheie: Fe-Mn-Si shape memory alloys, magnetic transition, mechanical alloying, powder metallurgy, thermal behavior

URL: http://www.springerlink.com/content/120454/