Aluminum nitride was bonded with a titanium foil at 1400 °C for up to 1 h in Ar. The A1N/Ti interfacial reactions were investigated using analytical electron microscopy. Reaction layers, consisting of δ-TiN, T2-Ti2A1N, γ-TiA1, Α 2-Ti3A1, a two-phase region (α 2-Ti3A1 + α-Ti), and α-Ti (A1, N) solid solution, were observed after annealing at 1400 °C for 0.1 h. Among these phases, the α2-Ti3A1 and (α2-Ti3A1 + α-Ti) were formed during cooling. Further diffusion of N atoms into the reaction zone precipitates a chopped fiber-like α2-Ti2AIN in the matrix of γ-TiA1, with [l10]γ-T iA1//[ll2̄0]T2-Ti 2A1N and (11̄1̄)γ- TiA1// (11̄03̄)T2-Ti 2A1N, by substituting N atoms for one-half A1 atoms after annealing at 1400 °C for 1 h. The released A1 atoms, due to the precipitation of T2-Ti2A1N, resulted in an ordered A1-rich γ-TiA1 or Ti3A15. Furthermore, the α-Ti (A1, N) was nitridized into a lamellar layer (δ-TiN + α-Ti) with [1l0]δ- TiN//[ll2̄0] α-Ti and (111)δ-TiN// (0001)α-Ti.