Article
Materials Science, Multidisciplinary
J. Li, C. Xu, G. Zheng, W. J. Dai, C. C. Bu, G. Chen
Summary: The study has found that the premature failure of enhanced creep strength martensitic steels in ultra-supercritical plants is mainly caused by the microstructural evolution of martensite and carbides. Using the multi-step TTP-LMP method, a three-stage creep rupture behavior under different stress regions has been confirmed.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Metallurgy & Metallurgical Engineering
Michal Junek, Marie Svobodova, Jakub Horvath, Vladimir Mara
Summary: This study focuses on the analysis of microstructure degradation and mechanical property degradation of P91 and P92 steels in orbital narrow-gap welding. It reveals that using orbital narrow-gap tungsten inert gas welding technology can improve welding efficiency and repeatability.
STEEL RESEARCH INTERNATIONAL
(2022)
Article
Mechanics
Yanyan Huang, Xiaowu Luo, Yucun Zhan, Yan Chen, Liping Yu, Wei Feng, Jiankun Xiong, Jianping Yang, Guijun Mao, Lin Yang, Fuheng Nie
Summary: This study investigates the creep rupture behavior and microstructure changes of dissimilar welded joints of two types of martensitic heat resistant steel: F92 and Co3W2. The results indicate that the fracture position and mode change from transgranular ductile fracture in parent F92 to intergranular brittle fracture in the fine grain heat affected zone near F92, with the decrease of applied stress. The study also reveals the microstructural degradation caused by creep, including the decrease in dislocation density, precipitates coarsening, formation of dislocation cells, microvoids, macroscopic secondary cracks, and changes in fracture surface morphology.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Nuclear Science & Technology
G. J. Zhang, Y. Zhou, J. F. Yang, H. Y. Yang, M. M. Wang, K. Jing, Z. M. Xie, L. C. Zhang, R. Liu, G. Li, H. Wang, L. Li, Q. F. Fang, X. P. Wang
Summary: 9Cr-F/M-xSi (x = 0-1.0 wt%) steels with a ferrite/martensitic structure and precipitated M23C6 and MX phases were fabricated and characterized. The addition of silicon led to an increase in ultimate tensile strength and hardness, while the total elongation remained constant. The solid solution strengthening mechanism played a more significant role than carbide precipitation. These findings have implications for the composition design of materials for nuclear reactors.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Materials Science, Multidisciplinary
Alexandra Fedoseeva, Ivan Nikitin, Evgeniy Tkachev, Roman Mishnev, Nadezhda Dudova, Rustam Kaibyshev
Summary: The study on P92-type steels with different chemical compositions showed that an increase in B and Cr contents affects the precipitation of M23C6 carbides, while (W+Mo) content influences the diffusion growth and coarsening of Laves phase. The addition of Re to 10%Cr steel can reduce the coarsening rate of Laves phase.
Review
Materials Science, Multidisciplinary
Martin Detrois, Jeffrey A. A. Hawk, Paul D. D. Jablonski
Summary: This review summarizes the recent development of creep-resistant ferritic-martensitic steels, which are essential materials used in power plants operating at high temperatures. The findings suggest that CPJ-7 steel has superior creep properties at 650 degrees C compared to other alloys, and the refined design of JMP steel shows potential for operation at the same temperature. The review also discusses the influence of various alloy elements on microstructure and mechanical properties.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Metallurgy & Metallurgical Engineering
Michael Hauser, Olena Volkova, Marco Wendler
Summary: The mechanical properties of two metastable austenitic cast steels were examined through tensile tests in a temperature range of -70 to 300°C. The M-s and M-d temperatures for the 16-6-6 steel were -30°C and 100°C, respectively. The possibility of athermal martensite formation below -196°C was excluded for the X3CrNiCuN17-6-4 steel. The M-d temperature for X3CrNiCuN17-6-4 steel was found to be 130°C. The results obtained from a semiempirical thermodynamic-mechanical calculation model were compared to experimental results from tensile tests.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Bernd Kuhn, Michal Talik
Summary: This paper discusses the influence of forming parameters on the microstructure and achievable creep properties of high-performance ferritic stainless steels. Thermomechanical treatment is shown to effectively enhance the creep strength of the materials, offering potential cost savings in component production.
Review
Materials Science, Multidisciplinary
Nadezhda Dudova
Summary: This paper provides an overview of the creep strength and microstructural features of 9% Cr and 10-12% Cr martensitic steels with high B and low N contents, achieved through modifying the chemical composition. The optimal B/N ratio in steels is discussed, and the creep properties are compared with those of traditional B and N content steels. The relationship between the stability of lath structure and precipitates and the creep strength of steels is also explored, along with future prospects of this alloying modification.
Article
Materials Science, Multidisciplinary
Yumeng Zhang, Huabing Li, Yabo Wang, Yixuan Hu, Hao Feng, Xiaodong Wang
Summary: The significance of pretreatment on the microstructure and mechanical properties of high nitrogen martensitic bearing steel was investigated. The specimen treated with spheroidizing and normalizing showed ultrahigh strength and improved plasticity (2303 MPa ultimate tensile strength, 4.8% elongation). This was attributed to the elimination of cementite networks, better distribution of carbides/nitrides through spheroidizing, and refined prior austenite grains by normalizing. The limited growth of martensite blocks can be attributed to the heredity characteristic of martensite microstructure from austenite. The fine retained austenite grains dispersed evenly in the martensite and contributed to plastic strain and stress concentration coordination.
Article
Metallurgy & Metallurgical Engineering
Stefanus Harjo, Takuro Kawasaki, Noriyuki Tsuchida, Satoshi Morooka, Wu Gong
Summary: In-situ neutron diffraction measurements were conducted on low-alloy steels and a 304-type stainless steel during tensile and creep tests at room temperature, revealing the relationship between intergranular stress in gamma and the occurrence of martensitic transformation during deformation. The susceptibility to martensitic transformation depended on the gamma-(hkl) grains, where gamma-(111) grains underwent martensitic transformation at the latest, and was controlled by shear stress levels in gamma-(hkl) grains affected by intergranular stress partitioning during deformation.
ISIJ INTERNATIONAL
(2021)
Article
Nanoscience & Nanotechnology
Amir Falekari, Hamid Reza Jafarian, Ali Reza Eivani, Mahdi Habibnejad-korayem, Akbar Heidarzadeh
Summary: Thick tempered martensitic steel plates were friction stir processed to form finer martensite phase and ferrite, leading to increased hardness. However, this process reduced the tensile strength and elongation, resulting in brittle fractured surfaces.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Shixing Chen, Jingchuan Zhu, Tingyao Liu, Yong Liu, Yudong Fu, Toshihiro Shimada, Guanqi Liu
Summary: This paper mainly studied the integrated computational materials engineering using database technology, machine learning, thermodynamic calculation, and experimental verification. The interaction between alloying elements and precipitated phases in martensitic ageing steels were investigated. Machine learning was applied for modeling and parameter optimization, achieving a prediction accuracy of 98.58%. The influence of composition fluctuation on performance and the influence of elements from multiple perspectives were analyzed through correlation tests. Thermodynamic calculations studied the effect of alloying element content on the nano-precipitation phase, Laves phase, and austenite. New steel grade heat treatment parameters were developed based on phase diagram, and a martensitic ageing steel with excellent mechanical properties was prepared.
Article
Materials Science, Multidisciplinary
Wen Zeng, Ming Zhou, Mei Yang, Risheng Qiu, Xinu Tan, Anruo Zhou, Xianfu Luo
Summary: The study investigated the effect of manganese content on the microstructure, mechanical properties, and high temperature oxidation resistance of RAFM steels. The results revealed that the steels exhibited a fully martensite structure with M23C6 carbides and Zr(C, N) carbonitrides. Increasing manganese content led to higher strength but decreased toughness. The optimum oxidation resistance was observed in the steel with 1.2 wt.% Mn due to the refinement of MnCr2O4 oxide diameter.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Nanoscience & Nanotechnology
Tomohiko Hojo, Motomichi Koyama, Bakuya Kumai, Yuki Shibayama, Ayumi Shiro, Takahisa Shobu, Hiroyuki Saitoh, Saya Ajito, Eiji Akiyama
Summary: The origins of the superior work hardening capability of medium manganese (M-Mn) and conventional transformation-induced plasticity-aided bainitic ferrite (TBF) steels of similar tensile strength and elongation are investigated. The work hardening capability of M-Mn steel is attributed to high rates of martensitic transformation and dislocation accumulation in retained austenite, while the work hardening capability of TBF steel is attributed to high austenite phase stability and resistance to slip deformation.
SCRIPTA MATERIALIA
(2022)
