An Atom Probe Study of Κ-Carbide Precipitation in Austenitic Lightweight Steel and the Effect of Phosphorus
The influence of phosphorus on κ-carbide precipitation and alloy partitioning in an austenitic Fe-30Mn-9Al-1Si-0.9C-0.5Mo cast steel was studied utilizing a combination of transmission electron microscopy, 3D atom probe tomography, X-ray diffraction, and first-principles atomistic modeling. Increasing the amount of phosphorus from 0.006 to 0.043 wt pct P increased the kinetics of the initial ordering reaction. Specimens from the high-phosphorus steel showed some degree of short-range ordering of Fe-Al-C that took place during the quench. It was shown that phosphorus increases both the size and volume fraction of κ-carbide during aging. However, the distribution of phosphorus appears to be homogeneous, and thus long-range diffusion of phosphorus was not responsible for the observed increase in hardening. It is shown that phosphorus encourages the initial short-range ordering into the E21 structure of κ-carbide and also accelerates spinodal decomposition associated with carbon and aluminum diffusions.
L. Bartlett et al., "An Atom Probe Study of Κ-Carbide Precipitation in Austenitic Lightweight Steel and the Effect of Phosphorus," Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, vol. 48, no. 11, pp. 5500 - 5515, Springer Boston, Nov 2017.
The definitive version is available at https://doi.org/10.1007/s11661-017-4287-3
Materials Science and Engineering
Keywords and Phrases
Alloy steel; Aluminum; Austenite; Carbides; Carbon; High resolution transmission electron microscopy; Manganese; Molybdenum; Precipitation (chemical); Probes; Reaction kinetics; Spinodal decomposition; Transmission electron microscopy; X ray diffraction, 3d atom probe tomographies; Atomistic modeling; Carbide precipitation; First principles; Light-weight steels; Long-range diffusion; Order reactions; Short range ordering, Phosphorus
International Standard Serial Number (ISSN)
Article - Journal
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01 Nov 2017