As-quenched microstructure of the Fe-23 at% Al-7 at% Ti alloy was a mixture of (A2+D0₃) phases. When the as-quenched alloy was aged at 1073 K for moderate times, D0₃ domains grew preferentially along ⟨100⟩ directions and extremely fine B2 particles occurred at a/2⟨100⟩ anti-phase boundaries (APBs). After prolonged aging at 1073 K, the B2 particles would grow to occupy the whole a/2⟨100⟩ APBs. Consequently, the stable microstructure of the alloy at 1073 K was a mixture of (B2+D0₃) phases.