A novel additive repair approach for Ti-6Al-4 V based on the extreme low heat input

Abstract

An innovative wire arc additive repair approach based on the extreme low heat input was proposed to repair the defect of Ti-6Al-4 V in this study. Arc was ignited between the tungsten electrode and hydrocooling Cu pipe over the substrate, avoiding arc acting on the substrate directly and resulting in a smaller heat affected zone (HAZ) and finer grains. While the top and middle region of repaired layer exhibited coarser grains with α and α’ martensite phases owing to the lower heat dissipation rate. Note that the thickness of HAZ was much lower than reported methods. And the hardness near fusion line was higher than other regions, attributed to the finer grains. The substrate was only affected by the molten droplet and little arc heat during repairing process, minimizing the thermal influence on the substrate. This study provided a novel perspective for wire arc additive repair technology.