Texture and grain-size effects on cyclic plasticity in copper and copper-zinc

Atomic force microscopy of the intense slip localization causing fatigue crack initiation in polycrystalline brass

“…Addition of 30% zinc to copper leads to a fatigue process of primary hardening, softening and secondary hardening [5][6][7][8], rather than hardening, saturation and secondary hardening. Nevertheless, transmission electron microscopy (TEM) [5,8] shows that the fatigue process in planar slip materials is associated with evolution of (planar) EDL nanostructures, so the nanotheory predicts that ISLs will form when the stress amplitude is high enough to cause EDL-splitting.…”

Cyclic Behavior and Damage Analysis of Brass under Cyclic Torsional Loading

“…Intergranular cracking dominated the fracture process. This can be correlated with the high intergranular stresses, which would be expected to result from planar slip [13].…”

“…The lack of a true saturation in cyclic hardening for brass complicates the choice of ''saturation stress'' criteria [10]. In our study, we have used the (dr/dN) min locus (i.e., the stress r min after N min cycles, where the slope (dr/dN) reaches the first minimum after hardening behavior) to plot the CSS curve as was done by Wang [9] and Carstensen [13]. As shown in Fig.…”

“…When the effective strain amplitude reaches approximately 3%, the saturation stress again increased with effective strain amplitude. This behavior may be attributed to the occurrence of the plastic strain localization in intense shear bands, which are a characteristic of polycrystalline CFC material [10,13,18].…”

“…Carstensen [13] suggested a Jackson-type cross-slip theory of primary cyclic hardening based on the assumption that Cu30%Zn was short-range ordered (SRO). The plastic strain during primary cyclic hardening was concentrated on coarse slip lines in the softer areas of the alloy and strain hardening proceeded by the formation of planar dislocation arrays.…”