Al partitioning in MA 956, an ODS ferritic stainless steel
- National Research Inst. for Metals, Tsukuba (Japan)
The hardening of binary Fe-Cr alloys during ageing at low temperatures (so-called 475 C embrittlement) has been shown, by atom probe field ion microscopy (APFIM), to be due to the spinodal decomposition of the supersaturated solid solution into Fe-rich {alpha} and Cr-rich {alpha}{prime} phases. Additionally, it has been shown that similar decomposition occurs in the cr-enriched ferritic phase of duplex stainless steels and in single-phase Fe-Cr based ternary and higher order alloys. The addition of alloying elements (Co, Ni, Si, Mo) to the binary Fe-Cr system has been shown to affect the kinetics and products of the decomposition process. These alloying elements themselves partition preferentially between the {alpha} and {alpha}{prime} phases, as the decomposition reaction proceeds. The driving force for their partitioning arises from the reduction in the free energy of the system. However, it has been shown recently that Al does not appear to partition preferentially to the Fe-rich {alpha} phase, as predicted thermodynamically, during ageing of up to {approx}600 hours at 475 C of MA 956, an Al-containing Cr-rich oxide-dispersion-strengthened (ODS) ferritic stainless steel. The aim of this work was to investigate the partitioning behavior of Al during phase separation of MA 956 when the {alpha} and {alpha}{prime} domains are expected to be in thermodynamic equilibrium.
- OSTI ID:
- 438615
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 3 Vol. 36; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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