Effect of Pre-Ageing on the Artificial Ageing Response of Al-Mg-Si(-Cu) Alloys
The effect of different pre-ageing treatments on the subsequent artificial ageing response of Al-Mg-Si(-Cu) alloys have been investigated using hardness, tensile and electrical conductivity testing. The microstructural evolution was characterised by differential scanning calorimetry (DSC) and 3-dimensional atom probe (3DAP) analysis. Pre-ageing treatments were carried out at 160-250°C for short times. Results show that the early stage artificial ageing response after 30 minutes at 170°C is strongly influenced by the pre-ageing and natural ageing conditions. A pre-ageing treatment performed for a short time at a high temperature and within a short delay after solution treatment and quenching was found to give a promising hardening response during subsequent artificial ageing. The mechanisms by which pre-ageing can reduce the detrimental effect of natural ageing on the artificial ageing response will be discussed in relation to the formation and distribution of clusters, GP zones and/or precipitates.
Jian-Feng Nie and Allan Morton
L. F. Cao et al., "Effect of Pre-Ageing on the Artificial Ageing Response of Al-Mg-Si(-Cu) Alloys", Materials Science Forum, Vols. 654-656, pp. 918-921, 2010