Application of Positron Annihilation Spectroscopy Studies of Bismuth and Subsurface Zone Induced by Sliding

Download or read book Application of Positron Annihilation Spectroscopy Studies of Bismuth and Subsurface Zone Induced by Sliding written by Jerzy Dryzek and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The positron annihilation, experimental and theoretical results obtained for bismuth are presented, mainly concerning the open volume defects created during compression and dry sliding. Positron lifetime in vacancy clusters increases with the size of the cluster; however, it saturates at the value of about 0.42 ns already for six vacancies in a cluster. Similar values were resolved in the positron lifetime spectra of bismuth samples exposed to dry sliding. Detection of the subsurface zone in bismuth exposed to dry sliding reveals exponential decay of vacancy clusters concentration with the depth increase from the worn surface. The high strain of about 70% was evaluated in the layer adjoined the worn surface The temperature of recrystallization obtained from the isochronal measurements of annihilation line shape parameter was equal about 90°C, and the activation energy for grain migration is about 0.84 ± 0.11 eV.