About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Additive Manufacturing and Innovative Feedstock Processing for Multifunctional Materials
|
| Presentation Title |
Constitutional Supercooling-Driven Grain Refinement in Laser Powder Bed Fusion of Ni-Fe-X Permalloys |
| Author(s) |
Nicolas Ayers, Amanda Chau, Yongho Sohn |
| On-Site Speaker (Planned) |
Nicolas Ayers |
| Abstract Scope |
Nickel–iron–molybdenum permalloy is a soft magnetic alloy for magnetic shielding, but its fabrication by laser powder bed fusion (LPBF) is limited by minor, yet persistent solidification cracking along columnar grains. This work explores constitutional supercooling (CS) as an inoculant-free route to grain refinement. The potency of a solute in promoting CS is captured by the growth restriction factor, Q: a strongly segregating solute, Si raises Q, increasing CS and promotes a columnar-to-equiaxed transition. Single laser scans of Ni–Fe alloy with 5 wt.% Mo (Q=2.6 K) and 5 wt.% Si (Q=42.1 K), and LPBF of 5 wt.% Mo and 4 wt.% Si demonstrated this effect: Mo addition yielded columnar grains and cracking, whereas Si additions produced refined crack-free microstructure. A subsequent solutionization recovered the single-phase FCC desired for soft-magnetic performance. The correlation between Q, microstructure, and cracking tendency establishes a translational alloy-design strategy for crack mitigation during LPBF. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Additive Manufacturing, Magnetic Materials, Solidification |