Simultaneous strength optimization and recrystallization prevention in induction-heating-assisted laser additively manufactured Ni-based superalloys

Abstract

Induction heating favors crack inhibition for laser additive manufacturing of Ni-based superalloys but may negatively influence columnar grain growth and mechanical properties. Here, by induction heating at a proper temperature during laser additive manufacturing, superalloys with a directionally solidified grain structure are obtained. Optimized γ′-precipitate size grants them higher microhardness than their counterparts either cast or additively manufactured without concurrent induction heating. Furthermore, lowered built-in dislocation density reduces the driving force for recrystallization. The combination of a maintained columnar grain structure, an increased microhardness, and a decreased risk of recrystallization offers a valuable pathway for advancing additive manufacturing of superalloys.

Keywords

• Laser additive manufacturing
• Ni-based superalloys
• concurrent induction heating
• strengthening mechanism
• recrystallization