|About this Abstract
||Materials Science & Technology 2019
||Corrosion of Additively Manufactured Metals
||Understanding the Influence of Retained Nitrogen in Additively-Manufactured 17-4 Stainless Steel: Does it Really Improve Corrosion Resistance?
||Mark R. Stoudt, Richard Ricker
|On-Site Speaker (Planned)
||Mark R. Stoudt
The additive manufacturing (AM) build process is known to introduce microstructural heterogeneities that promote variability in mechanical performance; however, the influence of these heterogeneities on corrosion resistance is not well understood. Wrought SS17-4 is an industrially-relevant heat-treatable alloy with a microstructure of delta-ferrite stringers in a martensite matrix, which generally exhibits high-strength and good corrosion resistance. When atomized in nitrogen, the as-built microstructure is a mixture of alpha-ferrite and austenite that does not readily transform to martensite. While, this substantially reduces the strength, the retained nitrogen has also been shown to enhance the corrosion resistance. Argon-atomized AM17-4 easily transforms to martensite but exhibits significantly higher porosity and reduced corrosion resistance with respect to the wrought alloy. The relationships between post-build heat treatment, microstructure and corrosion resistance were examined in environments with differing solution pH. The corrosion behaviors of wrought, nitrogen-atomized AM17-4, and argon-atomized AM17-4 will be compared and discussed.