Behavior of the Nickel-Titanium Alloys with the Shape Memory Effect under Conditions of Shock Wave Loading

The behavior of the Ti51.1Ni48.9 and Ti49.4Ni50.6 alloys with shape memory effects has been studied under submicrosecond shock wave loading in the temperature range from -80 to 160 degrees C, which includes both the regions of the stable state of the specimens in the austenite and martensite phases and the regions of thermoelastic martensitic transformations. The grain size of the studied alloys varies from initial values 15-30 to 0.05-0.30 mu m. The dependences of the dynamic elastic limit on the temperature and on the elemental composition are similar to the dependences of the yield stress of these alloys under low strain rate loading. The rarefaction shock wave formation as a consequence of the pseudoelastic behavior of the alloy during a reversible martensitic transformation has been revealed. A decrease in the grain size leads to an increase in the dynamic elastic limit and decreases the temperatures of martensitic transformations.