Nucleation process control of undercooled stainless steel by external nucleation seed
Competitive phase selection of undercooled melts between equilibrium ferrite and metastable austenite has been investigated as a function of undercooling. Stainless steel type 316 was undercooled up to 250 K using an electromagnetic levitation method. The microstructure showed different morphologies depending on the undercooling due to different solid phase transformation mechanisms. However, metastable austenite was not formed during the solidification for the undercooling up to 250 K due to the favorable nucleation kinetics of ferrite. The control of the phase selection has also been attempted using an external nucleation seed. Undercooled melts were touched by Fe-50 at.% Ni powders in the levitation coil, whose lattice constant is almost the same as that of metastable austenite. The microstructure showed a dramatic change in the solidification mode from equilibrium ferrite to metastable austenite during the first stage of the solidification.
- Research Organization:
- National Research Inst. for Metals, Tsukuba, Ibaraki (JP)
- OSTI ID:
- 20002020
- Journal Information:
- Acta Materialia, Vol. 47, Issue 14; Other Information: PBD: 26 Oct 1999
- Country of Publication:
- United States
- Language:
- English
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