NANOSTRUCTURED TITANIUM-NICKEL ALLOY WITH SHAPE MEMORY EFFECT AND METHOD OF MAKING BAR THEREOF

摘要

FIELD: metallurgy.SUBSTANCE: proposed alloy features structure of nanocrystalline grains of B2-phase wherein volume fraction of 0.1 mcm-size grains and those of shape factor of 2 in mutually perpendicular planes makes at least 90%. Over 50% of grains have large angular boundaries misaligned relative to adjacent grains through 15 to 90 degrees. Method of making the bar from said alloy comprises thermomechanical processing including plastic straining and recovery annealing. Intensive plastic straining is made in two steps. At first step, equal-channel angular pressing is made to accumulated strain e?4. At second step, forge ironing and/or drawing are made. Annealing is carried out either in process and/or after every straining step. Equal-channel angular pressing is performed at 400°C. Forge drawing and ironing are made to total reduction of over 60% at gradual decrease of temperature to t=450-200°C, while annealing is performed at t=400-200°C.EFFECT: higher mechanical and functional properties.2 cl, 2 dwg, 1 ex