High-Resolution Microstructure Characterization of Additively Manufactured X5CrNiCuNb17-4 Maraging Steel during Ex...

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• X5CrNiCuNb17-4 maraging steel is used in demanding applications.
• Selective Laser Melting (SLM) is a key additive manufacturing technique.
• Understanding powder properties' impact on SLM parts is crucial.

Purpose of the Study:

• Investigate the link between powder characteristics and microstructure in SLM maraging steel.
• Determine the role of powder irregularities and oxides in the final part.
• Assess the thermal stability and potential strengthening effects of formed nano-oxides.

Main Methods:

• Systematic electron microscopy analysis of powder and SLM parts.
• In situ heating experiments within a scanning transmission electron microscope (STEM).
• Characterization of oxide nanoparticles, copper clusters, and other precipitates.

Main Results:

• Powder particle irregularities and oxidation lead to beneficial nanoscale (AlMnSiTiCr) oxides.
• Nano-oxides exhibit remarkable stability in size, morphology, and composition up to 950 °C.
• Observed nucleation and evolution of copper clusters and precipitation of Ni/Cr particles.

Conclusions:

• Defects in SLM maraging steel powder can be advantageous.
• Nano-oxides offer potential for oxide-dispersive strengthening.
• This strengthening may improve high-temperature creep resistance.