| About this Abstract |
| Meeting |
2024 AWS Professional Program
|
| Symposium
|
2024 AWS Professional Program
|
| Presentation Title |
Role of Austenite Stability in Creep Performance of Gas Metal Arc Directed Energy Deposition Austenitic Stainless Steel |
| Author(s) |
Olivia Denonno, Juan Gonzales, Robert Hamlin, Stephen Tate, Jonah Klemm-Toole |
| On-Site Speaker (Planned) |
Olivia Denonno |
| Abstract Scope |
A gas metal-directed energy deposition process was used to fabricate builds using two commercial weld fillers used in power generation applications, 16-8-2 and 316H. The long-term microstructure stability and elevated temperature mechanical properties of the two austenitic stainless steels were investigated through room temperature and elevated temperature tensile testing and creep testing at 650 °C, 750 °C, and 825 °C. 16-8-2 exhibited reduced austenite stability which resulted in the formation of athermal martensite after aging at 650 °C for 1000 hours and strain-induced martensite formation during room temperature tensile testing. 316H exhibited relatively higher austenite stability due to increased alloying content resulting in no athermal martensite or strain-induced martensite formation. The lower austenite stability of 16-8-2 resulted in reduced creep performance at 650 °C compared to 316H. Ferrite formed during creep at 650 °C for 16-8-2 which resulted in reduced creep life and lower creep ductility compared to 316H. At 750 °C and 825 °C, when ferrite is no longer thermodynamically stable, 16-8-2 exhibited longer creep life and similar creep ductility as 316H. Upon cooling after creep testing, athermal martensite formation was observed for 16-8-2 samples that experienced long times at elevated temperatures. The formation of athermal martensite appears to have no impact on creep performance. The formation of ferrite in 16-8-2 appears to have a greater impact on creep performance than the formation of embrittling topologically close-packed phases like sigma phase seeing as 316H exhibited superior creep performance while it was predicted to form 14 vol % sigma phase at equilibrium at 650 °C. The results of this work show that phase stability is a critical criteria when selecting feedstock materials for GMA-DED produced components in high temperature structural applications. |
| Proceedings Inclusion? |
Undecided |