The effect of ion irradiation on the tensile and fatigue properties of Ti-6Al-4V alloy

The specimens of Ti-6Al-4V alloy were irradiated under the simulated ion beams of hydrogen and nitrogen. The microstructures of the alloy before and after irradiations are characterized by SEM, TEM and XRD. Then the tensile and high cycle fatigue properties were examined on the irradiated and un-irradiated alloys. The results show that the tensile and fatigue properties decrease to a larger degree after irradiation with the hydrogen ions than that with the nitrogen ions. The brittleness induced by the double effects of the fined grains and TiH is the main reason why the mechanical properties decrease for the alloy irradiated with the hydrogen ions. While for the alloy irradiated with the nitrogen ions, the decreasing properties are induced by the single effect of the partly fined grains. Therefore, the irradiation, especially with the hydrogen ions, plays a deleterious role on the properties of the alloy. The mechanisms of irradiation effect on properties are partly same for the alloy irradiated with nitrogen and hydrogen ions. The specimen shows a dyeing effect on the surface of the specimen after irradiation, which has no much influence on the mechanical properties of the alloy.