Effect of severe plastic deformation on the formation of the nanocrystalline structure and the aging of the multicomponent aluminum-lithium alloy with small additions of Sc and Mg

Acceleration of volume decomposition of supersaturated Al + 4 wt.% Cu solid solution under irradiation with Ar+ ions

“…A particularly good example of the above is accelerating solid solution decomposition in alloys subjected to severe plastic deformation (SPD). SPD activates the decomposition and changes its stagewise character as indicated in a number of papers .…”

“…It is shown in Refs. that the storage (natural aging) of the 1450 alloy (Al–Cu–Li–Zr–Mg–Sc), which was deformed by high pressure torsion, from 1 month to 1.5 years as well as its artificial aging at 150 °C for 15 h results in the formation of stable fine Т 2 (Al 6 CuLi 3 ) and S 1 (Al 2 LiMg) phases (instead of metastable δ ′ and θ ′ phases formed under the same aging conditions in the alloy with a conventional microcrystalline structure). Along with heterogeneous nucleation at nanograin boundaries , the internal mechanisms of their nucleation and growth from a supersaturated (not only with substitutional impurities, but also vacancies) solid solution into the grain volume intensify with increasing aging time.…”

“…Thus, SPD changes the mechanism and kinetics of the supersaturated solid solution decomposition in quenched aluminum alloys and causes the formation of fine stable‐phase particles which appear in the alloys not subjected to SPD, usually only at high‐temperature annealing. This SPD effect is due to an increase in the density of interfaces (nanograin boundaries) and lattice defects (dislocations and vacancies) .…”

Multicomponent Aging Al-Li-Based Alloys of the Latest Generation: Structural and Phase Transformations, Treatments, Properties, and Future Prospects

“…The boundaries of cells have presented by themselves wide tangles of dislocations; the diameter of the central parts of cells characteristic of a lowered number density of dislocations has varied from 0.3 to 1 µ m. A somewhat smeared shape of the reflections in the corresponding electron diffraction patterns has pointed out at a low-angle crystallographic misorientation between the cells. In this case, the presence of the δ' nano phase was recorded in the SAED pattern (insert in Figure 5а) [129,130]. An increase in the degree of HPT deformation always led to the disappearance of the dispersoids Al3(Zr, Sc) and to the formation of an equiaxed UFG structure characteristic of a grain diameter of 100-150 nm, with/of different, including high-angle, misorientation (Figure 5b,c).…”

“…A somewhat smeared shape of the reflections in the corresponding electron diffraction patterns has pointed out at a low-angle crystallographic misorientation between the cells. In this case, the presence of the δ' nano phase was recorded in the SAED pattern (insert in Figure 5a) [129,130].…”