Identification of different positron trapping sites during artificial aging of a commercial light weight alloy

Despite the great relevance of age hardenable light weight alloys, the underlying precipitate formation, especially the initial clustering stages are not fully understood yet. In a previous study, we could identify and analyze three main stages of the precipitation sequence in the commercial alloy AW6060. In the present study, additionally, we detected shallow positron traps attributed to solute clusters by temperature dependent measurements of the positron lifetime after distinct artificial aging times at 210°C. For a first sample, artificially aged for 1000 s, the existence of shallow positron traps was unambiguously proven whereas for a second sample, aged for 2 h, only the presence of a small fraction of shallow traps coexisting with a predominant fraction of β” precipitates could be concluded.