TY - GEN A1 - Kashkarov, Egor B. A1 - Nikitenkov, Nikolay A1 - Sutygina, Alina A1 - Laptev, Roman A1 - Bordulev, Yuriy A1 - Obrosov, Aleksei A1 - Liedke, Maciej O. A1 - Zak, Andrzej A1 - Weiß, Sabine T1 - Microstructure, defect structure and hydrogen trapping in zirconium alloy Zr-1Nb treated by plasma immersion Ti ion implantation and deposition T2 - Journal of Alloys and Compounds N2 - 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. KW - Zirconium KW - Ion implantation KW - Titanium KW - Diffusion KW - Surface modification KW - Hydrogen trapping KW - Microstructure KW - Slow positrons KW - Doppler broadening KW - Defects Y1 - 2018 UR - http://www.sciencedirect.com/science/article/pii/S0925838817335879 U6 - https://doi.org/10.1016/j.jallcom.2017.10.151 SN - 0925-8388 VL - 732 SP - 80 EP - 87 ER - TY - GEN A1 - Ryabchikov, Alexander I. A1 - Kashkarov, Egor B. A1 - Shevelev, Alexey A1 - Obrosov, Aleksei A1 - Sivin, D. O. T1 - Surface modification of Al by high-intensity low-energy Ti-ion implantation: Microstructure, mechanical and tribological properties T2 - Surface and Coatings Technology N2 - A high-intensity metal ribbon ion beam was generated using plasma immersion extraction and the acceleration of the metal ions with their subsequent ballistic focusing using a cylindrical grid electrode under a repetitively pulsed bias. To generate the dense metal plasma flow, two water-cooled vacuum arc evaporators with Ti cathodes were used. The ion current density reached 43 mA/cm2 at the arc discharge current of 130 A. High-intensity ion implantation (HIII) with a low ion energy ribbon beam was used for the surface modification of the aluminium. The irradiation fluence was changed from 1.5 × 1020 ion/cm2 to 4 × 1020 ion/cm2 with a corresponding increase in the implantation temperature from 623 to 823 K. The structure and composition of the Ti-implanted aluminium were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The mechanical properties and wear resistance were measured using nanoindentation and “pin-on-disk” testing, respectively. It was shown that the HIII method can be used to form a deep intermetallic Al3Ti layer. It has been established that a thin (0.4 μm) modified layer with a hcp Ti(Al) structure is only formed on the surface at 623 K, while the formation of the ordered Al3Ti intermetallic phase occurs at the implantation temperatures of 723 and 823 K. Despite the significant ion sputtering of the surface, the thickness of the modified layer increases from ~1 μm to ~6 μm, and the implantation temperature rises from 723 to 823 K. It was found that the homogeneous intermetallic Al3Ti layer with a thickness of up to 5 μm was formed at 823 К. The mechanical and tribological properties of the aluminium were substantially improved after HIII. For the Ti-implanted aluminium, the hardness of the surface layer increases from 0.4 GPa (undoped Al) to 3.5–4 GPa, while the wear resistance increases by more than an order of magnitude. KW - Ion implantation KW - Ribbon ion beam KW - Intermetallics KW - Aluminium KW - Titanium KW - Surface modification Y1 - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0257897219304992?via%3Dihub U6 - https://doi.org/10.1016/j.surfcoat.2019.05.020 SN - 0257-8972 VL - 372 SP - 1 EP - 8 ER -