Microstructure, defect structure and hydrogen trapping in zirconium alloy Zr-1Nb treated by plasma immersion Ti ion implantation and deposition

• Published in: Journal of alloys and compounds 2018-01, Vol.732, p.80-87
• Main Authors: Kashkarov, Egor, Nikitenkov, Nikolay, Sutygina, Alina, Laptev, Roman, Bordulev, Yuriy, Obrosov, Aleksei, Liedke, Maciej O., Wagner, Andreas, Zak, Andrzej, Weiβ, Sabine
• Format: Article
• Language: English
• Subjects: Defects; Deposition; Diffusion; Doppler broadening; Hydrogen storage; Hydrogen trapping; Hydrogenation; Ion implantation; Microstructure; Plasma; Positron beams; Slow positrons; Strong interactions (field theory); Surface modification; Titanium; Titanium base alloys; Trapping; Vacancies; Zirconium; Zirconium alloys; Zirconium base alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.10.151

The effect of low energy plasma immersion ion implantation and deposition of titanium on microstructure, defect structure and hydrogen trapping in zirconium alloy Zr-1Nb was studied. Defect structure and distribution were analyzed by Doppler broadening using slow positron beam. The surface microstructure after modification is represented by nanostructured Ti grains with random orientation. The gradient distribution of titanium as well as vacancy type defects were analyzed. The concentration of vacancy type defects is rising with increasing bias voltage. Gas-phase hydrogenation of the Ti-modified Zr-1Nb alloy was performed at 400 °C for 60 min. The strong interaction of hydrogen with vacancy type defects was demonstrated. Two different changes in the defect structure after hydrogenation were observed: when a titanium film is formed on the surface (after deposition at 500 V) hydrogen trapping occurs with the formation of titanium hydride phases, while in the implanted layer (deposition at 1000 and 1500 V) hydrogen is trapped due to interaction with vacancy type defects. The physical basis of Ti diffusion and its influence on the evolution of defect structure after surface modification and hydrogenation were discussed. •Zr-1Nb alloy was treated by plasma immersion Ti ion implantation and deposition.•A gradient distribution of titanium as well as vacancy type defects were shown.•Concentration and depth distribution of vacancy type defects was increased with bias.•The strong interaction of hydrogen with vacancy type defects was demonstrated.