Abstract
A three-dimensional (3D) knowledge of the atomic-scale structure is necessary for improving the design and understanding of modern materials with complex microstructures, such as high-performance steels. Local-electrode atom-probe tomography is used to obtain atom-by-atom 3D reconstructions to characterize three versions of a copper, nickel, manganese, and aluminum bearing high-strength low-carbon steel, which achieve their high tensile yield strength, up to 1170 MPa (170 ksi), from the formation of nanometer-radius copper rich precipitates. The temporal evolution of these precipitates is followed at 500 °C, and it is found that manganese and nickel segregate at their interfaces with the segregation level increasing with aging time. The segregation of carbon, boron, phosphorous and sulfur at grain boundaries is detected and correlated with poorer impact fracture toughness at higher segregation levels.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 35-40 |
| Number of pages | 6 |
| Journal | Scripta Materialia |
| Volume | 55 |
| Issue number | 1 SPEC. ISS. |
| DOIs | |
| State | Published - Jul 2006 |
Funding
This research is supported by the Office of Naval Research (N00014-03-1-0252); Dr. Julie Christodoulou, grant officer. Atom-probe tomographic analyses were performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT), and the LEAP tomograph was purchased with funding from the ONR-DURIP (N00014-0400798) and NSF-MRI (DMR-0420532) programs. Dr. Shrikant Bhat of Mittal-Ispat-Inland Steel Research Center is kindly thanked for providing the alloys used in this study. Semyon Vaynman, Northwestern University, is also kindly thanked for the provision of aged samples.
Keywords
- Ferritic steels
- Interfacial segregation
- Nanostructure
- Precipitation strengthening
- Temporal evolution
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys