Critical instability at moving keyhole tip generates porosity in laser melting

Abstract

Driving the pores away The formation of “keyholes” (vapor-filled depressions) during additive manufacturing leads to porosity, which degrades alloy performance, especially fracture properties, and remains a big challenge for the 3D printing of metals. Zhao et al. used high-speed x-ray imaging to take a detailed look at how keyhole formation connects to porosity in a titanium alloy. They found that instability at the keyhole tip drives pores away to get trapped in the solidification front. Understanding this process and the operating parameters under which it occurs provides a roadmap for avoiding porosity and building high-quality metal parts. Science , this issue p. 1080