Papers by Author: Oddvin Reiso

Abstract: Twelve different aluminium alloys with constant iron (Fe) and scandium (Sc) contents of 0.5 wt.% and 0.2 wt.%, respectively, were cast and subsequently homogenised. The distribution of Sc in the microstructure was examined by means of Energy Dispersive X-ray Spectroscopy (EDX) in Scanning Electron Microscope (SEM). Emphasis was put on measuring the solubility of Sc in the Fe-bearing phases of the investigated alloys. It was found that the amount of Sc tied up in Febearing phases is so low that it can be regarded as negligible, with the possible exception of α- AlFeMnSi (Al15(Fe,Mn)3Si2) and the π-phase (Al8FeMg3Si6). A quaternary AlFeSiSc phase with a composition close to Al10Fe3Si5Sc2 may have been discovered.

Abstract: Specimens of three Al-Mg-Si alloys, 6060, 6005 and 6082, were solution heat treated, stored at different temperatures for different time, and artificially aged. Properties were measured before and after artificial ageing. The natural ageing response of the alloys is dependent on the storage temperature. Decreasing storage temperature leads to a delayed onset of natural ageing, but also to a higher strength after prolonged ageing, particularly for lean alloys such as 6060. The temperature and time of intermediate storage between solution heat treatment and artificial ageing has a significant effect on the strength of the artificially aged material. For the 6005 and 6082 alloys the processes that take place during natural ageing lead to a reduced strength after artificial ageing.