The effect of thermal cycling and stress-assistant ageing two-way shape memory effect in [123]-oriented Co40Ni33Al27 single crystals

The effect of thermal cycling through an interval of B2-L10 martensitic transformation (MT) under action of external stress and tensile stress-assistant ageing on the two-way shape memory effect in [bar 123]-oriented Co40Ni33Al27 (at.%) single crystals are investigated. For the first time it is experimentally established that tensile stress-assistant 100 MPa ageing at 573 K for 1 h along [bar 123]-direction of Co40Ni33Al27 single crystals creates the necessary conditions for two-way shape memory effect (TWSME) with the reversible strain up to epsilon=2.4 (±0.3)% at cooling/heating. The TWSME in quenched [bar 123]-oriented Co40Ni33Al27 single crystals can be induced by thermal cycling through an interval of B2-L10 MT under action of constant external stress 50 MPa with the reversible strain less than 1%