Evolution of microstructures resulting from dendrite growth in undercooled Fe-Cr-Ni melts

Journal Article · Wed Jul 01 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00057-3· OSTI ID:644320

Moir, S A; Eckler, K; Herlach, D M ^[1]

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1. DLR, Koeln (Germany). Inst. fuer Raumsimulation

Experiments have been carried out for two alloys Fe{sub 69}Cr{sub 1}Ni{sub 30} and Fe{sub 69}Cr{sub 7}Ni{sub 24} to investigate the evolution of microstructures of steels grown from undercooled melts. The microstructures undergo several critical transitions as the undercooling at which solidification starts is increased. Firstly, grain size can change by up to an order of magnitude from small to large and back to small at critical undercoolings. Secondly, the segregation pattern changes from dendritic/equiaxed to dendritic and finally to equiaxed with increasing undercooling. Measurements from the segregation patterns indicate that the primary dendrites had undergone considerable Ostwald ripening depending on the processing conditions (heat-extraction rate). Relating the measured trunk sizes to an original trunk size through ripening and then applying this value to a recent model for grain refinement, which is based on dendrite fragmentation, yields a rough approximation to the critical transitions of the grain size.

• OSTI ID: 644320
• Report Number(s): CONF-9704224--
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 11 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM ALLOYS
DENDRITES
IRON ALLOYS
LIQUID METALS
MICROSTRUCTURE
NICKEL ALLOYS
SEGREGATION
SOLIDIFICATION