Creation of high-nitrogen steel with silicon nitride powder additivation

Influence of Si3N4 powder additivation on PBF-LB processability of stainless steels and microstructural evolution during PBF-LB and a subsequent HIP-URQ densification process

Motivation

The range of materials for the Powder Bed Fusion - Laser Beam process (PBF-LB) is severely limited by the thermal process conditions. Through the development of additive powders, the range of materials for this process can be significantly expanded. The basis for this is provided by conventional AM (additive manufacturing) powders, which are mixed with a wide variety of metallic, ceramic or polymer powders and are thus available to the PBF-LB as additivated powders. The influence of these additives on the powder properties (flowability, bulk density, etc.), the usability by PBF-LB and the particle dissolution, as well as the behavior during thermal post-treatment by hot isostatic pressing (HIP) are currently not fully understood

Objectives

The goals of the project are basically defined by the properties of the newly developed alloy systems through additivation using Si3N4:

• Increased strength due to interstitially dissolved N atoms
• Consistently good ductility of stainless steels despite additivation with Si3N4
• Increased corrosion resistance due to Nitrogen as alloying element
• To perform a sensitivity analysis on the influence of particle size distribution and process parameters on the processability of the additivated powder

Project Contents

• Powder atomization and additivation
• PBF-LB processing
• HIP-URQ/ thermal post-processing
• Microstructure analysis
• Characterization of mechanical/ electrochemical properties

  

Project partner

Chair of Materials Technology at the Ruhr University Bochum

Funding

Funded by German Research Society within SPP 2122: Materials for Additive Manufacturing