Mechanism of the element microsegregation induced corrosion difference of Ti6321 weldment

Herein, we studied the effect of element on corrosion behaviour and on the corrosion films of different zones of a Ti6321 weldment in 5 M hydrochloric acid. The welded material zone (WM) with a lower inner potential difference showed better anti-corrosion properties than that of the base material zone (BM) and heat-affected zone (HAZ). Obvious element microsegregation detected via TEM between the adjacent α- and β-phases of the BM and HAZ, resulting in increasing galvanic corrosion tendency and a deteriorated corrosion film for these zones. Therefore, element microsegregation endangers Ti-based weldments for marine applications.