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.
- 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
- Metallurgy and
- Physics
Available at: http://works.bepress.com/david-vanaken/111/