Growth of nanosized chemically ordered domains in intermetallic FeAl made nanocrystalline by severe plastic deformation

Severe plastic deformation using high-pressure torsion leads to a partial destruction of the B2 long-range order in FeAl. Transmission electron microscopy methods reveal that chemically ordered nanodomains of medium-range size (about 2 nm) are formed. These nanodomains are separated by antiphase boundaries and homogeneously distributed within the grains. Upon heating, the order is restored by coarsening of the ordered nanodomains until the size of the ordered domains reaches the grain size.

Research highlights
► Severe plastic deformation of B2 long-range ordered FeAl leads to chemically ordered nanodomains and not to a statistical reduction of order.
► The presence of chemically ordered nanodomains of medium-range size (about 2 nm) is revealed by transmission electron microscopy.
► Re-ordering occurs upon heating by coarsening of the domains until they reach the size of the grains.
► During deformation by high pressure torsion the temperature rise of the sample is <30 K.