Polycrystalline nickel is implanted with 150 keV phosphorus ions to a dose of 5 × 1016 ions/cm2 at room temperature. The specimens with and without phosphorus implantation are tested in load‐unload tensile fatigue under stress‐controlled condition, and the implanted surface layer is investigated with AES, SEM, and TEM. It is found that the implanted surface region consists of an amorphous NiP phase and a Ni3P compound. Corresponding measurements of microhardness indicate that phosphorus implannation enhances the surface microhardness of nickel. A 19% increase in the endurance limit is found after phosphorus implantation. Compared with the unimplanted specimens under the same fatigue conditions, the number of surface grains in which slip bands could be found decreases, the slip bands become finer and homogeneous, and the surface is smooth. It is also found that the cyclic loading at room temperature can lead to migration of implanted phosphorus out of the surface layer and recrystallization of amorphous NiP phase. Possible strengthening mechanisms for these experimental results are discussed.

A binary Al–Co decagonal quasicrystal has formed after 100 keV Co+-ion implantation into pure Al with a dose of 1.5×1017 ion/cm2, and the quasicrystal has shown a high thermal stability. The composition of stable decagonal quasicrystal is believed to be Al11Co4. Co+ ion implantation into Al first produced a multiple layer surface structure. The first layer was an amorphous layer. The second layer consisted of a decagonal quasicrystal and a coexisting amorphous phase. The amorphous phase in the implanted region where composition is close to Al11Co4 was transformed into the decagonal quasicrystal during annealing in a temperature range between 550 and 600 °C. Possible transformation mechanisms for the experimental results are discussed.