Effect of strain rate on impact response and ω transformation of quenched Zr-Nb alloys

The strain rate sensitivity of impact response of quenched Zr-Nb alloys was experimentally investigated. The ω phase transformation with extremely high nucleation frequency is shown to cause a quite effective stress relaxation leading to the presence of stress plateau in the work hardening stage of stress-strain curve and the negative relationship between stress and strain rate. Besides, the habit plane for the impact induced ω phase transformation is the same as usually found for the thermally induced ω phase transformation. It is suggested that numerous ω particles in deformed samples may nucleate from the vacancies induced by impact loading.