Positron annihilation lifetime and Coincidence Doppler Broadening (CDB) experiments have been performed to study the nature of Cu precipitates and vacancy type defects in Fe, Fe-Cu and Fe-Cu-C alloys after Fe(2+) and Cu(2+) ion implantations. In all alloys after ion irradiations, long lifetime component tau2 of about 300 psec, which corresponds to a vacancy cluster of about 5 or more vacancies, was measured. In the CDB ratio curve to pure Fe, the appearance of broad peak, which shows the characteristic feature of Cu, depends on Cu concentration. The values of doppler broadening S parameter were slightly different by a kind of impurity atom existing in. On the other hand, it was found that CDB ratio curve of Fe(2+) ion irradiated Fe-Cu alloy is not necessarily similar to that of Cu(2+) ion irradiated Fe.