Nondestructive positron-lifetime measurements during fatigue of austenitic stainless steel using a mobile positron beam

Abstract

Nondestructive positron-lifetime measurements have been performed during stress-controlled symmetric fatigue of austenitic stainless steel up to failure for different applied stress amplitudes between 230 and 300 MPa. For this purpose a fatigue machine has been equipped with a mobile positron beam emitted from a 22 μCi (0.8 MBq) Se/7272As generator. A pronounced increase of the mean positron lifetime has been found within the first 10% of fatigue life. Saturation has been reached after 40% of fatigue life. The mean positron lifetime at failure depends strongly on the applied stress amplitude.

Reverse transformation of deformation-induced martensite in austenitic stainless steel studied by positron annihilation

“…PAS can be used for identification and tracking of changes of crystal lattice defects, i.e., their generation during deformation or their annealing. These techniques have been successfully used for non-destructive evaluation of fatigue damage in SSs [31][32][33] and detection of the subsurface zone defects created by sliding, cutting [34,35], or shot peening [36]. PAS was applied to determine vacancy migration energy in SS [37,38].…”

Stable transport of relativistic electron beams in plasmas

“…Collimated relativistic electron beams (REBs) with high energy are widely used in astrophysics, inertial confinement fusion (Craxton et al 2015;Yang et al 2016), plasma based accelerators (Geddes et al 2004;Esarey, Schroeder & Leemans 2009) and new diagnostic technologies (Barbieri et al 2000). In these areas, many potential application scenarios such as space active experiments (Marshall et al 2014;Borovsky & Delzanno 2019;Xue et al 2020) in the middle atmosphere require long-distance transport of electron beams.…”