Modification of Inconel 718 Properties by In Situ Y Addition in Selective Laser Melting

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• Inconel 718 is a high-performance superalloy widely used in demanding applications.
• Modifying alloy properties through additive manufacturing techniques is crucial for advanced material design.
• Selective laser melting (SLM) offers potential for in situ alloy property enhancement.

Purpose of the Study:

• To investigate the effect of in situ yttrium addition on the microstructure and mechanical properties of Inconel 718 processed by selective laser melting.
• To determine the optimal yttrium content for property modification in SLM-processed Inconel 718.
• To understand the role of undissolved yttrium particles on material performance.

Main Methods:

• Selective laser melting (SLM) of Inconel 718 with varying yttrium concentrations (0.1-2% by mass).
• Single and double laser processing per layer.
• Microstructural analysis to identify yttrium particle distribution and phase composition.
• Tensile testing to evaluate yield strength, tensile strength, and relative elongation.

Main Results:

• Undissolved yttrium particles were observed in the Inconel 718 matrix.
• Hardness of the alloy generally increased with higher yttrium content.
• An initial increase in yttrium (0-0.1%) led to decreased yield and tensile strength but improved elongation.
• Higher yttrium concentrations (>0.1%) resulted in a significant decrease in elongation and increased yield strength, attributed to undissolved particles.

Conclusions:

• In situ yttrium addition can modify Inconel 718 properties during SLM.
• Low yttrium content (around 0.1%) appears beneficial for enhancing ductility.
• The presence of undissolved yttrium particles significantly impacts mechanical behavior, necessitating careful control of processing parameters and yttrium addition.