METHOD FOR TREATMENT OF SINGLE CRYSTALS OF FERROMAGNETIC CONIAL ALLOY WITH CONTENT OF Ni 33 -35 at AND Al 29 -30 at

摘要

FIELD: metallurgy.;SUBSTANCE: method for treatment of single crystal of ferro-magnetic CoNiAl alloy with Ni content 33 -35 at % Al 29 -30 at % for introducing the two-way shape memory effect includes annealing of samples at +1330C÷1340°C for 8.5 hours in inert gas atmosphere followed by quenching in water and thermomechanical treatment. The thermomechanical treatment is carried out per heating/cooling cycle involving heating in free state of single crystal in the form of parallelepiped placed in the grippers of the test machine in planes (001)_B2, (110)_B2, up to 275°C, applying compressive load of 500 MPa along the crystallographic direction cooling under load to the temperature of 0÷-50°C until completion of thermoelastic B2-L1₀ martensitic transformation, heating to the temperature of 125°C for 1 hour in martensitic state and further heating to the temperature of 275°C to complete reverse martensitic transformation L1₀-B2 The load is then removed and cooled to room temperature. The heating/cooling rate during thermomechanical treatment is 5-7°C/min.;EFFECT: high cyclic stability of the two-sided shape memory effect when thermocycling in free state at room temperature.;1 tbl