Alloy ТН-1В is an intermetallic compound characterized by thermoelastic martensitic transformation, shape memory, and superelasticity. Deformation hysteresis of martensitic transformations in titanium nickelide is a fundamental phenomenon. The most significant reasons for its development are dissipative processes and entropy production. In the paper, peculiar features of the hysteresis in titanium nickelide ТН-1В prone to phase hardening are investigated. The nature of transformation hysteresis and structure of the energy dissipation are studied. Thermodynamic (dissipation of heat fluxes) and mechanical (structure imperfection) are identified as two competing contribution to production of the entropy of transformation. Area of hysteresis loop of sample under loading is investigated in depth due to the hysteresis being the characteristic of energy dissipation in a cycle of thermoelastic martensitic transformations under loading. Magnitude of mechanical energy loss is evaluated and compared with results of calculations for different values of loading.