EFFECT OF SURFACE MODIFICATION BY NITROGEN AND OXYGEN ON MECHANICAL PERFORMANCE OF Zr-1%Nb ALLOY

The effect of surface modification by oxygen and nitrogen from a controlled gaseous medium on the fatigue life under cyclic and long-term static loading of Zr-1%Nb alloy thin-sheet samples was studied. Positive effect of gas nitriding and thermal oxidation on mechanical and fatigue performance under cyclic and static loading of Zr-1%Nb alloy was shown: under pure bending – by ~23%; under cyclic stretching – by ~25% and under long-term static loading in air with exposure of 100 h at room temperature – by ~12% and at a temperature of 380 °С  by ~6%. It was established that oxidation and nitriding effectively improve fatigue life and fracture stresses under long-term static loading of Zr-1%Nb alloy thin-sheet.