Investigation of the interaction between hydrogen and irradiation defects in titanium by using positron annihilation spectroscopy

The formation of mono-vacancy, vacancy clusters and hydrogen-vacancy complexes with 30 keV H ion-irradiated pure titanium at different doses and temperatures was measured using by Positron annihilation spectroscopy (PAS). Results show a large number of HmVn clusters and vacancy-like defects in the samples irradiated at for room temperature, and that the formation of HmVn (m > n) at the sample irradiated at a high dose inhibits the increase of the S parameter. At increased irradiation temperature, the shrinkage of vacancy clusters and the effective open volume of defects decrease the S parameters. The high temperature irradiation results in decreased vacancy-type defect concentration, and some hydrogen atoms diffuse from the cascade region to the track region, forming a large number of hydrogen-vacancy complexes in the track region. The coincidence Doppler broadening spectroscopy, an element analysis method, used to detect hydrogen in the ion irradiated pure titanium sample, and results show hydrogen-related peaks in the high momentum region, which may be due to the information of positron annihilation in the covalent bond formed by the H and the Ti elements. The increased radiation dose and temperature contribute to the formation of the hydrogen vacancy-complex, and the positron annihilation in high-momentum regions easily obtain hydrogen-related information. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the formation of hydrogen-vacancy complexes and vacancy-like defects in pure titanium irradiated with H ions at different doses and temperatures. It was found that increasing irradiation temperature led to a decrease in vacancy cluster size and effective open volume of defects. High temperature irradiation decreased the concentration of vacancy-type defects and promoted the formation of hydrogen-vacancy complexes in the track region. Increased radiation dose and temperature contributed to the formation of hydrogen vacancy-complexes and facilitated the detection of hydrogen-related information through positron annihilation in high-momentum regions.