A novel method to prevent cracking in directed energy deposition of Inconel 738 by in-situ doping Inconel 718

Research question

Can interlayer material design reduce cracking during directed energy deposition of crack-sensitive Inconel 738?

Method

Thin Inconel 718 interlayers are introduced during Inconel 738 deposition to form a layered gradient structure. Microstructural observations and tensile tests at room temperature, 600 °C and 800 °C examine precipitation, internal stress and mechanical performance.

Main findings

The studied composite deposits showed no observed macro- or micro-cracks. Inconel 718 interlayers altered the spatial distribution of γ′ precipitation and produced a combination of strength and ductility across the tested temperatures, demonstrating a material-design route to improved deposition behavior.