  Linear complexions are defect states that have been recently discovered along
dislocations in body centered cubic Fe-based alloys. In this work, we use
atomistic simulations to extend this concept and explore segregation-driven
structural transitions at dislocations in face centered cubic alloys. We
identify a variety of stable, nanoscale-size structural and chemical states,
which are confined near dislocations and can be classified as linear
complexions. Depending on the alloy system and thermodynamic conditions, such
new states can preserve, partially modify, or completely replace the original
defects they were born at. By considering different temperatures and
compositions, we construct linear complexion diagrams that are similar to bulk
phase diagrams, defining the important conditions for complexion formation
while also specifying an expected complexion size and type. Several notable new
complexion types were predicted here: (1) nanoparticle arrays comprised of L12
phases in Ni-Fe, Ni-Al, and Al-Zr, (2) replacement of stacking faults with
layered complexions comprised of (111) planes from the Cu5Zr intermetallic
phase in Cu-Zr, (3) platelet arrays comprised of two-dimensional
Guinier-Preston zones in Al-Cu, and finally (4) coexistence of multiple linear
complexions containing both Guinier-Preston zones and L12 phases in ternary
Al-Cu-Zr. All of these new complexion states are expected to alter material
properties and affect the stability of the dislocations themselves, offering a
unique opportunity for future materials design.
