The Effect of Ion Irradiation (Аr⁺, E = 15−20 keV) on the Microstructure of the Deformed Ni – 13.9 wt.% W Alloy

Using X-ray diffraction analysis, the effect of Ar⁺ ions with an energy of 15−20 keV (at ion current densities of 100−300 μA/cm²) on the microstructure, the level of internal microstresses and the texture of cold rolled ribbons of alloy Ni – 13.9 wt.% W is studied. It is found out that short-term irradiation of 80 μm thick ribbons with a fluence of 3.1·10¹⁶ cm^–2 (for 50 s) at temperatures T ≤ 370°C and T = 630°C leads to a decrease in microstresses in their entire volume, while the original texture is retained. With an increase in the fluence to 9.7·10¹⁷ cm^–2 at T = 630°C, the texture changes from (220) to (200). Changes in microstresses and texture on the irradiated and non-irradiated sides of 80-μm-thick ribbons are comparable to each other, despite the fact that the projected range of Ar⁺ ions with an energy of 15−20 keV in the alloy is only ~7 nm. It is known that annealing of such ribbons in an oven (700°C, 30 min) does not cause their recrystallization. At 850°C, the microstresses are relieved and the texture dramatically changes from (220) to (200) both as a result of annealing in a furnace (15 s) and as a result of irradiation with a fluence of 3.2·10¹⁶ cm^–2 for 17 s, but the effect of stress removal in the course of furnace annealing is 3 times lower than that of irradiation. Thus, the following facts have been established: 1) the occurrence of recrystallization processes in the alloy under study during irradiation at a temperature lower than the temperature of the onset of thermally activated recrystallization and 2) a higher rate of microstress drop (and to lower values) in the course of irradiation than during furnace annealing. This indicates a significant role of nanoscale radiation-dynamic effects at the cascade-forming irradiation of metastable media.