The effect of pre-ageing temperature and retrogression heating rate on the strength and corrosion behaviour of AA7150

The effects of processing condition variations in the retrogression and re-ageing (RRA) treatment of AA7150 have been investigated. The results reveal that the corrosion resistance and strength of RRA-treated samples are sensitive to the pre-ageing temperature and retrogression heating rate. With an intermediate pre-ageing temperature of 60 °C and a slow retrogression heating rate of 5 °C/min, RRA-treated samples can be tailored towards a good combination of both corrosion resistance and strength, owing to a smaller potential difference between grain-boundary precipitates and the matrix, and a larger volume fraction of strengthening precipitates in the matrix.

► The balance of properties for AA7150 is sensitive to ageing process.
► Better properties were achieved by 60 °C pre-ageing and 5 °C/min reversion heat rate.
► This work adds evidence to the findings about corrosion behaviour of aged 7xxx alloys.