1. Effect of pre-deformation on hydrogen diffusion and hydrogen induced damage in commercially pure titanium.
- Author
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Song, Zhian, Wang, Qianqian, Yang, Qigui, Zhu, Te, Yu, Xiaotian, Shi, Yunmei, Ma, Rui, Wan, Mingpan, Zhang, Peng, Yu, Runsheng, Wang, Baoyi, and Cao, Xingzhong
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DISLOCATION density , *POSITRON annihilation , *HYDROGEN , *HYDROGEN atom , *THERMAL desorption , *TITANIUM hydride , *DEUTERIUM - Abstract
[Display omitted] • High density dislocations inhibit hydrogen atoms diffusion. • Different types of hydrides were identified by CDB spectrum and theoretical calculations. • Hydrogen concentration decreases with increasing dislocation density. This work aims to elucidate the interaction between hydrogen atoms and pre-introduced dislocations in commercially pure titanium (CP-Ti). Positron annihilation spectroscopy supplemented by the first-principle calculations was utilized to reveal the effects of dislocation densities on the formation of hydride types and the concentration of hydrogen-induced defects in CP-Ti. Results show that, in the hydrogen-charged sample with 40 % deformation, hydrogen-induced damage gradually decreases when the hydrogen enters the sample at a depth of about 350 nm. This finding suggests that the high-density dislocations present in deformed specimens effectively trap hydrogen atoms and inhibit their diffusion, which ultimately mitigate damage within the samples. γ-TiH and δ-TiH 2 hydrides are observed in the hydrogen-charged sample. The thermal desorption spectroscopy results show that the desorption amount of deuterium decreases from 1.14 × 1018 D/cm2 to 5.10 × 1017 D/cm2 with an increase in dislocation density because dislocations inhibit the diffusion of deuterium. In samples with higher deformation, the high dislocation density inhibits the formation of δ-TiH 2 hydrides and promotes the formation of γ-TiH hydrides, which significantly reduce the hardening of samples. These results provide insight into the interaction of hydrogen with pre-introduced defects and provide strong theoretical support for the development and improvement of more damage-resistant materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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