[en] Mechanical properties of polycrystalline GFE-1 hafnium strained by rolling at 300 K with ? degrees e=18...70 % were studied. The non-monotone dependence of proportional limit, yield strength and ultimate strength from the degree of rolling was found out. As a result of ultrasonic action with amplitudes of stresses, comparable with the yield strength, the effects of work-hardening of material are discovered in an anneal state and softening - in deformed, that caused by generation of defects and relaxation of internal stresses, accordingly.