Research of Cu clusters and Cu–V complexes formed at early aging stage in FeCu alloys by low temperature positron spectroscopy

The precipitation process of tiny Cu clusters in the early stage of aging for FeCu alloys was investigated by positron annihilation lifetime spectroscopy (PALS), Doppler broadening spectroscopy (DBS) and coincidence Doppler broadening spectroscopy (CDB). The different effect of quenching and aging on the formation of Cu precipitates and Cu–V complexes in FeCu alloys was discussed. The Cu–V complexes and Cu clusters act as the shallow positron trapping sites has been confirmed. Their ability to trap positrons can be enhanced at lower temperature, which can be used to measure the behavior of fine Cu clusters at the beginning of aging. The Cu–V complexes, Cu clusters and monovacancies were formed after quenched at 1173 K. After aged at 773 K for 0.1 h, Cu–V complexes and monovacancies recovered while the Cu precipitates formed.