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Ausscheidungsveränderungen von ferritisch‐martensitischem 11 % Chromstahl beim Kurzzeitkriechen
Author(s) -
Zhou X.,
Shen Y.,
Shi T.
Publication year - 2019
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201800122
Subject(s) - creep , materials science , carbide , martensite , metallurgy , laves phase , chromium , martensitic stainless steel , diffusionless transformation , microstructure , alloy , intermetallic
A ferritic‐martensitic (FM) 11 % chromium steel with final heat treatment was subjected to a short‐term creep test at a stress of 150 MPa and 600 °C for 1100 h in order to study the change of precipitates in the steel during the creep test. Except for Nb‐rich metall carbides (MC, M 23 C 6 ) and Laves phases, Fe‐W‐Cr‐rich M 6 C (based on Fe 3 W 3 C) carbides forming during the creep test were also identified in the crept steel by electron diffraction and x‐ray diffraction in combination with energy dispersive x‐ray analysis of extraction carbon replicas. The identified M 6 C carbides have a fcc crystal structure, a metallic element composition of approximately 44Fe, 32 W, and 20Cr in atomic %, and large sizes ranging from 100 nm to 300 nm in diameter. The M 6 C carbides are a dominant phase in the crept steel. M 6 X precipitates are generally not easy to form during high temperature creep, even if it is a long‐term creep, in ferritic‐martensitic 9–12 % chromium steels with a final heat treatment. The present work provides the evidence for the M 6 C carbides forming during short‐term creep in ferritic‐martensitic high chromium steels. The formation of the M 6 C carbides was discussed.