Abstract
As-quenched microstructure of the Fe-24.6 at% Al-7.5 at% Ti alloy was a mixture of (A2+L21) phases. When the as-quenched alloy was aged at 1173 K for moderate times, the L21 domains grew considerably and B2 phase was formed at a/2⟨100⟩ anti-phase boundaries (APBs) as well as phase separation from well-grown L21 to (B2+L21*) occurred basically contiguous to the APBs, where L21* is also a L21-type phase. With continued aging at 1173 K, the phase separation would proceed toward the whole well-grown L21 domains. This microstructural evolution has not been reported in the Fe-Al-Ti alloy systems before.
