蠕动
材料科学
微观结构
延展性(地球科学)
冶金
马氏体
电子背散射衍射
奥氏体
氮化硼
复合材料
作者
Ernst Plesiutschnig,Coline Béal,Paul Shrivastava,Günter Zeiler,Stefan Mitsche,Christof Sommitsch
出处
期刊:Materials Science Forum
日期:2014-05-23
卷期号:783-786: 1867-1871
被引量:5
标识
DOI:10.4028/www.scientific.net/msf.783-786.1867
摘要
Over the past three decades a lot of effort was made to optimize the chemical compositionof 9% Cr martensitic steels, aiming to increase the operating temperature up to 923K and thus im-proving the efficiency of thermal power plants. Under these service conditions (high temperature andstress exposure), the creep strength of such steels is closely related to the long term stability of theirmicrostructure. The time to rupture can also be understood as an equivalent to the time of microstruc-ture deterioration. Optimization of the initial microstructure and understanding of the microstructureevolution during creep exposure are therefore decisive to improve the creep behavior of 9% Cr steels.Selected chemical compositions of MarBN steels (Martensitic 9% Cr steels strengthened by Car-bides, Nitrides and Boron) were subjected to different heat treatments to produce an optimized mi-crostructure to improve the creep rupture time. The initial microstructure before creep exposure wasinvestigated using optical microscopy, SEM and EBSD. Short term creep rupture tests at 923K and150MPa were performed, followed by systematic microstructure investigations.Comparative EBSD investigations confirm an optimized microstructure for creep exposure, pro-duced by an appropriate heat treatment. From comparative creep test results, it can be concluded thatadvanced microstructures increase the time to rupture of the selected MarBN steels by more than 10percent, without reduction of the ductility.
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