complex stress state with different intensity of the strain rate . During these experiments the specimens of HFPM in
the form of the hollow cylinders were loaded by the proportionally changed tensile force and torque. The series of
the tests were performed at the two-step program of changing the strain rate intensity. In these tests the specimens
were loaded some time with the slow strain rate intensity 0.023 s-1 to the specified level of the deformation, i ε . After
that, the additional loading of specimen was followed with grater rate of strain 1.94 s-1 to the fracture moment. The
example of the dependence of the stress intensity on the strain intensity is shown in Fig. 5 (right). The sharp kink of
the diagram at the change of the strain rate was cased the stress relaxation during the strain rate switching. The series
of the same tests were carried out for different combinations of the strain rate and the step duration. The evaluations
of critical damage were calculated for every test by using of considered criteria. The narrow values of the damage at
the moment of fracture were obtained by using both criteria: 0.93- by using deformational criterion and 0.95 by
using the energy criterion.