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The electron work function (EWF) of ultrafine grained (UFG) aluminum structured by high pressure torsion (HPT) has been investigated. For the first time, the dependence of the EWF on the specific length of grain boundaries (or the grain size) for UFG Al has been obtained. The change of average grain size was achieved by short term annealing of HPT-processed aluminum at different temperatures from the range 90-400 °C. It has been shown that the state of grain boundaries (GBs) affects the magnitude of the EWF. It has been found that the transformation of GBs due to annealing at 90 °C from a nonequilibrium to more equilibrium state while maintaining the specific length of GBs and their average misorientation is accompanied by a decrease in average GB specific energy by 0.3 J m-2. This transition provides a sharp increase in the EWF of the UFGAl by 0.25 eV.

Abstract: The samples of Ti2NiCu rapidly quenched alloy with different fractions of crystalline phase have been prepared by electric pulse technique from as spun amorphous ribbons. The structure and thermomechanical properties of these samples have been studied. The mixture of amorphous and nanocrystalline structures with mean grains size less than 10 nm has been observed by HRTEM. The remarkable thermomechanical properties of the samples with the ratio of crystalline fraction in the range of (determined by electrical resistivity measurements) have been found. The two-way shape memory effect with the reverse deformation has been induced in the sample with by single deformation at cooling below the temperature of martensite transformation. The prototype of microtweezers based on amorphous-nanocrystalline Ti2NiCu melt-spun ribbon alloy with two-way shape memory effect has been designed and tested. [ABSTRACT FROM AUTHOR]

Highlights: [•] Samples of Ti2NiCu alloy were annealed by electric pulse and annealing in DSC. [•] The spherulites nucleation and growth was observed in samples annealed in DSC. [•] 10nm grains was found in the samples after electric current annealed. [•] New crystalline grains nucleate during pulses of electric current without growth. [ABSTRACT FROM AUTHOR]