To obtain high temperature shape memory alloys of the lower cost Ni-Ti-X system, elements such as Hf and Zr are introduced to modify the thermal and mechanical properties of these alloys. This work studied the production and characterization of Ti50 Ni50-x Zrx alloys (x = 0, 5, 10 at.%) with the aim of improving their thermal, mechanical and corrosion resistance properties. In the resulting alloys, transformation of phase B2 into phase B19' occurred in a single stage. The addition of zirconium led to an increase of transformation temperatures, as well as the appearance of second phase particles in the grain boundaries of the matrix. The increase in zirconium percentage favored the increase of corrosion resistance from 520.23KΩ to 1007.30KΩ and of microhardness from 346HV to 543HV for the N0 and N10 alloys, respectively.

ABSTRACT In the present work, PTA welding process was used to investigate the influence of welding parameters on the dilution, microhardness and corrosion resistance of Inconel 625 alloy coatings on the API 5L X70 grade steel. The electrochemical impedance spectroscopy (EIS) and linear potentiodynamic polarization (LPP) measurements were used to study the protection properties of the deposited layer when immersed in a 3.5% NaCl solution. The results of EIS and LPP have shown that the corrosion resistance results were more satisfactory for coatings with higher dilution index. The results also showed that the dilution values D (%)varied from 15.33% to 4.39% at the maximum (18.99 kJ/cm) and the minimum (8.34 kJ/cm) welding energy levels. The most relevant dilution value obtained was 4.39%.

Abstract Different polymeric matrices have been investigated for use in the development of biodegradable films. The incorporation of cellulose nanocrystals in such films has particularly attracted attention because of the potential for achieving improved properties of starch nanocomposites. In the present study, cellulose nanocrystals were extracted from coconut fibers and incorporated in cassava and potato starch films at different concentrations. The properties of the different nanobiocomposite films were comparatively evaluated, including their barrier and mechanical properties. All the films, regardless of the nanocrystal concentration, were found to exhibit low solubility in water, with increased moisture content particularly observed in the films with higher nanocrystal concentrations. The potato starch film with the lowest nanocrystal concentration was found to exhibit the best mechanical properties. The observations of this study indicated that the source of the starch and the nanocrystal concentration determined the properties of the nanobiocomposite films.