Grain refinement in aluminum alloy 2219 during ECAP at 250 °C

Mechanical Properties of Fine-Grained Magnesium Alloys Processed by Severe Plastic Forging

“…The continuous increase in misorientations between (sub)grain boundaries evolved during deformation is an essential feature of cDRX, and the kinetics can be discussed by using the relationship between the average (sub)grain boundary misorientation (θ AV ) and total accumulated strain . The θ AV -ε relationships for Al alloy 2219 ECAPed at 523 K (Mazurina et al, 2008), a pure Cu MDFed at 195 K to 473 K (Gao et al, 1999, Belyakov et al, 2001, Kobayashi et al, 2007 and Mg alloy AZ31 compressed at 673 K are represented in Fig. 8.…”

Mechanisms of Dynamic Recrystallization in Aluminum Alloys

“…No formation of GNBs takes place in dilute aluminum alloys at high temperatures even under equal channel angular pressure (ECAP) that provides simple shear and, therefore, extensive slip localization in the ECAP shearing plane [7,11,13,14]. High value of the SFE provides a high ability of lattice dislocations to rearrange at elevated temperatures in aluminum and its alloys [6] that hinders the formation of 3D arrays of (LAB) with moderate-to-high misorientation [7].…”

“…Aluminum alloys exhibit high stacking fault energy (SFE) and continuous dynamic recrystallization (CDRX) is the main mechanism of dynamic grain refinement in a wide temperature range [6,7]. However, the fully recrystallized structure evolves only at sufficiently large strain [6][7][8][9][10][11][12][13][14]. Any decrease in the critical strain imposed into an aluminum alloy to produce sub-micrometer scale or nanoscale structure is extremely important.…”

“…The occurrence of CDRX could be highly facilitated through initial deformation banding [7,11,13,14]. At cold-to-warm working, geometrically necessary boundaries (GNBs) with initial low-angle misorientation [7,15] begin to appear at moderate strains, introducing large misorientations.…”

“…Subdivision of the original grains into 3D arrays bounded by dislocation boundaries with low-angle misorientation takes place. It is apparent that this process plays a vital role in initiating CDRX at low and intermediate temperatures [7,11,13,14].…”