About this Abstract |
| Meeting |
2025 AWS Professional Program
|
| Symposium
|
2025 AWS Professional Program
|
| Presentation Title |
Effects of Composition and Cooling Rate on Solidification Mode and Solid-State Phase Transformation in Iron-Nickel Alloys |
| Author(s) |
Richard Li, Joris Hochanadel, Boyd Panton, Carolin Fink |
| On-Site Speaker (Planned) |
Richard Li |
| Abstract Scope |
This study investigated the effects of composition and cooling rate on solidification mode and microstructure in Fe-Ni alloys. Arc-melted Fe-Ni ingots (20g) were fabricated with measured compositions ranging from 0.04-99.3 wt.% Fe. Light optical microscopy revealed evidence of solidification substructure in ingot compositions below 94.4 wt.% Fe, indicating primary austenitic solidification. From 95.4 wt.% Fe to 96.8 wt.% Fe, partial substructure implied mixed mode solidification, while no evidence of substructure and therefore primary ferritic solidification was observed in ingot compositions above 96.8 wt.% Fe. Laser melts were then performed on all ingots at 50 and 100 mm/s travel speed to vary solidification conditions. All laser melts exhibited full solidification substructure in the fusion zone up to 96.8 wt.% Fe. A change in solidification mode between the ingot and laser melts was attributed to higher solidification rates in the laser melts. A Kurz–Giovanola–Trivedi dendrite growth model was utilized to predict the primary solidification mode and compared with experimental results. Electron backscatter diffraction analysis revealed that below 51.8 wt.% Fe and above 79.5 wt.% Fe, the ambient temperature phases were indexed as FCC and BCC respectively in both the arc-melted ingot and the laser melts. Martensite was evident in Fe-Ni composition ranges from 79.5-99.3 wt.% Fe and verified with microhardness measurements. A cooling rate dependence for martensite formation was observed at and above 94.4 wt.% Fe. |
| Proceedings Inclusion? |
Undecided |