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

“…The GNBs evolve at the most stressed {111} planes owing to high strain gradients within narrow zones of plastic deformation (Fig.3a) [20]. Simple shear providing a very high-slip concentration in one {111} plane, and therefore, the deformation technique providing simple shear is highly capable of producing UFG structure in aluminum alloys [8,[11][12][13][14]. The subdivision of initial grains by GNBs to 3D crystallites requires a continuous strain path change to make none-coplanar GNBs (Fig.3b).…”

“…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].…”

“…However, these processes require elevated temperatures and higher strains. The introduction of nanoscale dispersoids of Al 3 (Sc,Zr) leads to 50K increase in the optimal temperature for extensive grain refinement [8,[11][12][13][14]. As a result, the deformation-induced boundary may originate partially from GNBs and partially evolve by rearrangement of lattice dislocations by climb [8].…”

“…This process provides the transformation of GNBs to sub-boundaries (Fig.3c) and is a prerequisite condition for a high rate of the (iii) process of CDRX. The combination of extensive deformation banding, which provides initial grain subdivision and introduce high misorientation, high stability of 3D arrays of sub-boundaries due to a high Zener drag pressure and a low portion of the lattice dislocations annihilated, allows producing UFG after relatively moderate strain [7][8][9][10][11][12][13][14]. Therefore, intermediate temperatures are optimal for the production of UFG structure in aluminum alloys.…”