The microstructural state of two grades of the creep-resistant austenitic stainless steels NF709, a Fe-20Cr-25Ni (wt%) based steel, has been studied, in the as-received state, after an additional solution-treatment and after static ageing at 1023 and 1073 K. Although the two variants are chemically similar, they exhibit different microstructures following identical heat-treatment. In particular, Z-phase and σ are found in largely different quantities. The study suggests that a seldom observed variant of the η structure, Cr3Ni2SiX, is stabilised by nitrogen. Both steels exhibit a yet undocumented precipitation sequence when compared to more conventional austenitic steels (for which the precipitation sequences have been reviewed).
Metallurgical and Materials Transactions A Vol. 36A, 2005, pp. 23-34.
NF709_1 |
NF709_10a |
NF709_10b |
NF709_11 |
NF709_12a |
NF709_12b |
NF709_13 |
NF709_14a |
NF709_14b |
NF709_14c |
NF709_15 |
NF709_16a |
NF709_16b |
NF709_16c |
NF709_17a |
NF709_17b |
NF709_2a |
NF709_2b |
NF709_2c |
NF709_3a |
NF709_3b |
NF709_4a |
NF709_4b |
NF709_5a |
NF709_5b |
NF709_5c |
NF709_5d |
NF709_5e |
NF709_5f |
NF709_5g |
NF709_6a |
NF709_6b |
NF709_7a |
NF709_7b |
NF709_8a |
NF709_8b |
NF709_8c |
NF709_8d |
NF709_9a |
NF709_9b |
Zipped file of postscript format figures.
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