Structure and thermomechanical properties of fast-quenched Ti2NiCu alloy ribbons with various crystalline phase fractions obtained by means of annealing by electric current

Resumo

New promising functional materials—amorphous-crystalline fast-quenched Ti₂NiCu alloys exhibiting the shape memory effect (SME)—are studied. A method for annealing amorphous alloys by electric current pulses is proposed. This method allows one to obtain the needed degree of crystallinity. It is demonstrated that a microcrystalline structure with spherical grains exists in amorphous-crystalline samples. These grains increase in size from 150 nm to 3.2 μm as the degree of annealing increases. The SME is not observed in nontreated samples and is clearly manifested in completely annealed samples. A two-way SME and a trend toward lowering of the martensitic transition temperature are observed in partially annealed samples.