On the Heterogeneous Distribution of Secondary Precipitates in Friction-Stir-Welded 2519 Aluminium Alloy

The macro-scale distribution of secondary precipitates in friction-stir-welded 2519 aluminium alloy was studied. It found that precipitation pattern essentially varied within the stir zone terms volume fraction, size, and even preferential concentration particles, either at grain boundaries or interior. This effect attributed to local variations welding temperature cooling rate, which led complex phenomena including coarsening, dissolution, partial reprecipitation. Specifically, coarsening most pronounced weld root due lowest being this area. On other hand, highest upper surface enhanced dissolution process. reprecipitation phenomenon deduced be prominent nugget slowest rate microstructural region.