The Influence of Trace Elements (In, Sn) on the Precipitation Process in AlCu-Alloys by Small Angle X-Ray Scattering, DSC and PALSWednesday (08.11.2017) 15:20 - 15:40 Part of:
AlCu-based alloys have important applications as high-strength and lightweight materials for the fuselage in aviation (AlCuMg, AlCuLi) and as cast-alloys (AlSiCu) for engine blocks in the transport sector. However, adding trace elements to these alloys can significantly improve their strength, while the underlying atomic mechanisms of nucleation are so far only superficially understood. We follow the precipitation process, i.e. changes in the micro structure by Small Angle X-ray Scattering (SAXS), giving information on size and density of precipitates. In situ SAXS measurements during the ageing process of the alloys give insight on the precipitation kinetics as well as the interaction between trace elements and vacancies. These results correlate very well with our data acquired by Differential Scanning Calorimetry (DSC), giving information on formation and dissolution of precipitates and finally, positron annihilation spectroscopy, being sensitive especially to quenched-in vacancies and their interaction with alloying elements. By the use of these complementary methods we obtain information on vacancy binding to the alloying elements and also on structure, kind and distribution of precipitates while correlating this with hardness measurements.