Fe ions were implanted into α-Al2O3. single crystals （sapphire） at energy, of 50 keV to a dose of 1×10^17 ions/cm^ 2 at room temperature. The mierostructure in the implanted region was studied by transmission electron microscopy. With annealing in a reducing atmosphere, the implanted Fe ions precipitate as the α-Fe particles. Some α-Fe particles are attached to voids. The large iron particles greater than 20 nm and some voids clearly have faceted outlines. Most of the α-Fe particles have the orientation relationship （OR） of （ 111 ）α-Fe// （0001）sapphire. and 1 1^-0α-Fe// 11 2^-0sapphire with sapphire. Only a small quantity of the α-Fe particles have the deviation from this OR and the maximum deviation is less than 3°. This OR is predicted precisely by the method of coincidence of reciprocal lattice points. Another OR of （110）.α-Fe//（0001）sapphire and 〈 111 〉 α-Fe// 〈 5 1^- 4^-0 〉 sapphire reported before is confirmed to be secondary preferred orientation in the α-Fe/ sapphire system.