Mechanical properties of titanium nickelide at high strain rate loading

Mechanical parameters of Ti–51.2 at.% Ni shape memory alloy (SMA) at dynamic loading on a Split Hopkinson Pressure Bar (SHPB) apparatus have been studied. It has been found out that at compression of the specimens in the martensitic state the phase and dislocation yield stresses, differing six times one from another, grow at the same rate with the increase of the strain rate. At the same time the work hardening coefficients on the stages of the phase deformation and the dislocation plastic flow are practically equal and do not change with an increase of the strain rate. The slope of the first apparently elastic part of a stress–strain curve has a constant value for strain rates in the range 800−1500 s−1, while the slope of the second apparently elastic stage of the deformation monotonously grows with an increase of the strain rate from 300 to 1500 s−1.