Microscopic analysis of the influence of ratcheting on the evolution of dislocation structures observed in AISI 316L stainless steel during low cycle fatigue

A synchrotron X-ray and electron backscatter diffraction based investigation on deformation and failure micro-mechanisms of monotonic and cyclic loading in titanium

“…This is also reflected in very low GROD values given in Table 2 indicating predominant intra-granular distortion only. The increase in dislocation density for strain control samples compared to stress control sample has also been observed in AISI 316L [15] and pure copper [16]. tensile samples is reached.…”

“…In the past, detailed TEM analysis has been carried out on the cyclic creep behavior of polycrystalline copper explaining the phenomenon of acceleration and deceleration of steady state creep rate occurring due to "strain burst" involving disruption and rearrangement of dislocation cell structure [15]. Such organization of dislocation cell structure of saturated dislocation density occurs in the habit plane along the slip direction, which is responsible for strong anisotropy in fatigue life during ratcheting [16].…”

Multiaxial fatigue behavior of AISI 316L subjected to strain-controlled and ratcheting paths

“…This observation can be explained considering the fact that, as reported by Doong et al [42], under non-proportional loading conditions the continuous change of the principal stress and strain directions promotes a stronger interaction between different slip systems compared to the proportional loading case. It is plausible that this interaction prevents the activation of the particular microstructural evolution mechanisms observed by Facheris et al [43] under uniaxial ratcheting conditions. A very similar dislocation structure for specimens subjected to non-proportional LCF and ratcheting experiments would explain the nearly identical mechanical response noticed in the current work.…”

Localized strain evolution and accumulation at the notch tip of an aluminum single crystal under cyclic loading

“…However, all these strain components did not reveal much strain accumulation along the backward band, and almost negligible plasticity had occurred in the region near to the notch surface. Moreover, because of the cyclic hardening of the metals during the load, and also due to progressive strain accumulation (as strain ratcheting/progressive strain accumulation causes increase of dislocation density 40,41 ), these bands were widespread along with indistinguishable sector boundaries. This observation was similar to the results of a hardening single crystals like Cu or Cu‐Be under monotonic load as cited by Crone and Shield 15,16 .…”