Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1599517 | Acta Metallurgica Sinica (English Letters) | 2006 | 8 Pages |
Abstract
It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy (CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the Lâδ transformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5°C/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150°C/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150°C/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
G.F. Liang, C.Q. Wan, J.C. Wu, G.M. Zhu, Y. Yu, Y. Fang,