Competitive grain boundary segregation of phosphorus and carbon governs delamination crack in a ferritic steel
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)
- National Institute for Nanomaterials Technology (NINT), POSTECH, Pohang 790-784 (Korea, Republic of)
- Gwangyang Sheet Products Research Gr., POSCO Technical Research Lab., Gwangyang 545-090 (Korea, Republic of)
Highlights: • Trace amounts of P in the steel cause delamination in case of Lt-high Temp. holding. • Anisotropic microstructure did not affect the delamination in this study. • Crack-linked GBs in Lt-high Temp. steel had higher P and lower C segregation. • Crack-interrupt GBs in St-high Temp. steel had lower P and higher C segregation. • Competitive segregation controlled by high Temp. holding time affects delamination. - Abstract: The present study aims at unveiling the influence of trace amounts of phosphorus on the macro-scale delamination in a ferritic steel. Two different steels with trace amounts of phosphorus were examined to reveal the cause: One was made by long-time high temperature holding to maximize the phosphorus segregation, and the other one was made by short-time high temperature holding to minimize the phosphorus segregation. The atom probe results at the grain boundaries ahead of the delamination-related cracks provide a strong evidence that phosphorus-enrichment and carbon-depletion for the long-time high temperature holding induces a larger degree of delamination as compared to the short-time high temperature holding. Reasons for the different segregation tendency were discussed by correlating the isothermal holding time at high temperature and the competitive segregation between phosphorus and carbon.
- OSTI ID:
- 22805866
- Journal Information:
- Materials Characterization, Journal Name: Materials Characterization Vol. 145; ISSN 1044-5803; ISSN MACHEX
- Country of Publication:
- United States
- Language:
- English
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