Correlation of ageing precipitates with the corrosion behaviour of Cu-4 wt.% Ti alloys in 3.5 wt.% NaCl solution

•The influence of artificial ageing on the corrosion behaviour of Cu-4wt%Ti alloys in 3.5 wt.% NaCl solutions was studied.•All specimens were susceptible to both intergranular and pitting corrosion.•The pitting corrosion susceptibility decreased with increasing ageing time.•The presence of abundant cellular β-Cu4Ti precipitates refined microstructures in specimen aged at 773 K for 24 h, provided “enveloping effect” and dramatically improved the corrosion resistance.•The corrosion resistance properties of the aged Cu-4 wt.% Ti alloys followed the order: over-aged > peak-aged > early aged > solution treated.

The influence of artificial ageing on the corrosion behaviour of Cu-4 wt.% Ti alloys in 3.5 wt.% NaCl solution was studied. Corrosion tests showed that ageing treatment changed the corrosion morphology of the alloys. All specimens were susceptible to both intergranular and pitting corrosion. The pitting corrosion susceptibility decreased with increasing ageing time. In particular, the presence of abundant cellular β-Cu4Ti precipitates refined microstructures in specimen aged at 773 K for 24 h, providing “enveloping effect” that dramatically improved the corrosion resistance. The corrosion resistance of the aged Cu-4 wt.% Ti alloys followed the order: over-aged > peak-aged > early-aged > solution treated.