Investigation of morphological, structural, and mechanical characteristics of Zircaloy-4 irradiated with 3.5 MeV hydrogen ions beam

Abstract

Zircaloy-4 specimens were irradiated with 3.5 MeV hydrogen ions (dose range: 1 × 1013 H+1 cm−2 to 1 × 1015 H+1 cm−2) using a Pelletron accelerator. FESEM studies reveal formation of hydrogen micro-bubbles, bubbles induced blisters of irregular shapes, and development of cracks on the specimen surface, as in the case of pure zirconium. However, for the highest irradiation dose of 1 × 1015 H+1 cm−2, agglomeration of flower-shape blisters is observed. XRD analysis shows that the most preferentially oriented crystallographic plane is (0 0 4) with texture coefficient values 1.832–2.308 depending on the ions dose. Its diffraction peak intensity first decreases with the increase in ions dose up to 5 × 1013 H+1 cm−2 and later increases up to 1 × 1015 H+1 cm−2. Opposite is found in case of diffraction peak width. Crystallite size and lattice strain determined by Williamson–Hall analysis display a linear relationship between the two with positive slope. Mechanical strength, namely yield stress (YS), ultimate tensile strength (UTS), and fracture stress (FS), increases sharply with ions dose up to 5 × 1013 H+1 cm−2. For 1 × 1014 H+1 cm−2 dose there is a sudden drop of stress to a lowest value and then a slow steady increase in stress up to the highest dose 1 × 1015 H+1 cm−2. Same pattern is followed by uniform elongation and total elongation. All three stress parameters YS, UTS, and FS follow Inverse Hall–Petch relation.