Characterization of the Defect Depth Profile of Shot Peened Steels by Transmission Electron Microscopy

Author:  Martin, Altenberger, Scholtes, Kremmer, Oettel
Source:  Conf Proc: ICSP-6, (p.142-153)
Doc ID:  1996061
Year of Publication:  1996
Abstract:  
Cylindrical specimens of the plain carbon steel SAE 1045 and the sustenitic steel AISI 304 were shot peened under similar conditions. The resulting properties of near surface regions were characterized in a conventional way using x-ray diffraction techniques and micro hardness measurements. In addition, a special cross sectioning technique was applied for transmission electron microscopy (TEM) preparation. The aim of the TEM-analysis was to investigate depth profiles of dislocation configurations. For that purpose, characteristic parameters of the dislocation arrangements such as dislocation densities or cell espectivesubgrain diameters were quantitatively determined. The results of these observation were detainled discussion of the stengthening mechanisms. Furthermore, shot peened specimens were fatigued up to certain numbers of cycles. a characteristic syslic hardening/softening behaviour of the specimens was observed, connected with microsturctural alterations and severe effects on residual stress profiles.