Stability of strengthened niobium alloys in long-term high-temperature loading conditions

Variations in structure and heat resistance of niobium alloys after long-term loading (for up to 10 000 h) in vacuum at 1173 and 1373 K are studied. It is concluded that niobium alloys are more heat-resistant while those undergoing solid-solution hardening are more stable structurally. It is shown that long-term strength plots for niobium alloys have kinks which are to be taken into account when predicting life of structurally unstable materials.