Article
Materials Science, Multidisciplinary
Dechao Lyu, Tieshan Cao, Tongtong Zhou, Congqian Cheng, Jie Zhao
Summary: The cyclic deformation mechanism and fracture characteristics of Sanicro25 alloy were investigated. The results showed that increasing the mean stress and stress amplitude led to higher cyclic strain rates and shorter fracture life. The relationship between the minimum strain rate and mean stress followed a power-law equation, with similar apparent stress exponent values at different stress amplitudes. The apparent activation energy increased with stress amplitude. Threshold stresses decreased with increasing temperature and stress amplitude. The cyclic strain process was found to be controlled by lattice self-diffusion, and the rupture life could be normalized using a modified Monkman-Grant equation.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Liming Xu, Yinsheng He, Yeonkwan Kang, Jine-sung Jung, Keesam Shin
Summary: This study investigates the precipitation evolution in HR3C steel at elevated temperatures of 700 degrees C and 750 degrees C. The main precipitates observed during creep exposure are Z-phase, M23C6, and r phase. Z-phase precipitates dispersedly in the austenite matrix along dislocation lines, while M23C6 preferentially precipitates at grain boundaries. Additionally, a brittle sigma phase is formed during long-term creep at high temperatures.
Article
Materials Science, Multidisciplinary
Xin Zhu, Chengbin Shi, Huai Zhang, Jing Li, Jun Liu
Summary: The influence of cooling rate on solidification characteristics, eutectic NbC, and Laves phase in 15Cr-22Ni-1Nb steel was investigated through in situ observation and microstructure characterization. Increasing the cooling rate led to an increase in the initiation and finishing solidification temperatures of the steel, as well as the solidification temperature interval. The rate constant of austenitic nucleation and growth decreased with increasing cooling rate, resulting in an increase in the nucleation rate of austenite. The microsegregation degree of certain elements increased with higher cooling rates, leading to the generation of eutectic NbC and Laves phase.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Jiaxu Wang, Wei Shi, Song Xiang, Ronald G. Ballinger
Summary: By using EPMA and TEM, it was found that there is a corrosion-sensitized zone around the grain boundary of high-nickel austenitic stainless steel 904L, with no significant element segregation, and the presence of sigma phase near the grain boundary.
Article
Chemistry, Multidisciplinary
Di Zhang, Yingtao Su, Xingrui Yang, Huilan Sun, Zhihong Guo, Bo Wang, Cheng Ma, Zhongqi Dong, Liguang Zhu
Summary: Based on rapid solidification technology, Cu is incorporated into soft magnetic materials to achieve grain refinement. Cu dosage not only refines the average grain size to 8.7 µm but also improves the continuity and consistency of Fe-6.5 wt % Si steel strip. This is mainly attributed to Cu-rich particles precipitating at the grain boundary, which inhibit grain growth and improve magnetic and mechanical properties. The addition of 1.5 wt % Cu results in excellent magnetic properties and about 11% failure plastic deformation for the steel strip. This technology also has reference value for modifying the mechanical and magnetic properties of other metal materials.
Article
Chemistry, Multidisciplinary
Ramasis Goswami, Alex Moser, Chandra S. Pande
Summary: This study reports the non-recrystallization behavior of a cold-worked Cu-Al2O3 composite at elevated temperatures. The composite, fabricated through internal oxidation, exhibits fine Al2O3 particles and a high density of Cu2O particles, which effectively inhibits grain boundary migration and recrystallization process.
Article
Materials Science, Multidisciplinary
Yu. M. Kuskov, Kh. R. Zadorozhna, V. D. Makarenko, V. A. Tishchenko, G. N. Gordan, I. L. Bogaychuk, T. V. Kaida
Summary: In this study, corrosion testing was conducted on austenitic-martensitic steel deposited on 40Kh steel samples using a Pd-Np-30Kh22MN flux-cored wire with a diameter of 2.2 mm and a single layer with 50% overlapping of the rollers under a layer of AN-26 flux. The results indicated that the best operating characteristics under the influence of corrosive media were achieved through surfacing with pulses of electrode wire supply of 0.7 Hz.
Article
Chemistry, Physical
Wenhao Ren, Limin Wang
Summary: The precipitation behavior of M23C6 carbides in LF25 high nitrogen austenitic heat-resistant steel was investigated and four morphology types were identified, including intergranular precipitates, parallel plate-like precipitates, cellular precipitates, and intragranular precipitates. The M23C6 carbides retained a cube-on-cube crystallographic relation with the matrix. The precipitation process was influenced by factors such as diffusion rate, stress, and atom volume difference.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Bogdan Rutkowski, Krzysztof Baran, Remigiusz Bloniarz, Tomasz Koziel
Summary: Alloy 709 was oxidized at 700 degrees C for 500 hours in a steam environment, forming a complex, multilayered oxide scale with an outer layer of Fe2O3 and the detection of Fe2NiO4 tI28 spinel underneath. Advanced electron microscopy techniques were used to characterize the morphology of the oxide scale, revealing an internal oxidation zone in the innermost layer. High-quality SEM-EDS maps provided insight into a larger area of the oxide scale at lower magnifications.
Article
Materials Science, Multidisciplinary
Matruprasad Rout, Surjya K. Pal, Shiv Brat Singh
Summary: In this study, the microstructure evolution of austenitic stainless steel after deformation at elevated temperatures was investigated through thermo-mechanical processing. The results showed that at temperatures of 900 degrees C and 1000 degrees C, the microstructures of samples held for 2 seconds consisted of deformed grains, while the sample held at 1100 degrees C showed nearly complete recrystallization. The increase in holding time resulted in a decrease in low angle boundaries and an increase in high angle grain boundaries at all three temperatures.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Metallurgy & Metallurgical Engineering
Hua Yu, Chen Jianguo, Yu Liming, Si Yonghong, Liu Chenxi, Li Huijun, Liu Yongchang
Summary: This study investigated the vacuum diffusion-bonding of dissimilar materials between high Cr ferritic and TP347H austenitic heat-resistant steel. The effects of diffusion-bonding time and post weld heat treatment (PWHT) process on the microstructural evolution and mechanical properties of the diffusion-affected zone were examined. The results showed that with the extension of diffusion-bonding time, the interfacial bonding rate gradually increased, resulting in the evolution of fine grains and serrated interface. After PWHT, the grains in the diffusion-bonding zone were further refined, dislocations were stable, and element diffusion was more sufficient.
ACTA METALLURGICA SINICA
(2022)
Article
Materials Science, Multidisciplinary
Chao Liu, Peng Jin, Tielong Shen, Zhiguang Wang
Summary: The microstructural evolution and dissolved oxygen of the oxide film formed on 15-15Ti austenitic stainless steel during early oxidation in steam at 500 degrees C were investigated. A triplex oxide structure consisting of outer Fe-rich layer, inner Cr-rich layer, and Ni-rich transition layer was observed. The relationship between corrosion resistance and oxide structure was discussed, and a mechanism for pore formation in the inner oxide layer of austenitic steel was proposed based on Ni's spatial distribution and migration behavior during oxidation.
Article
Nanoscience & Nanotechnology
Matruprasad Rout, V. Murugabalaji
Summary: In this study, single-pass hot rolling was conducted on 304LN austenitic stainless steel at different initial sample temperatures. Tensile samples were prepared to investigate the variation in through-thickness tensile properties. The microstructure of the rolled samples was examined using the electron backscattered diffraction (EBSD) technique. Significant differences in ultimate tensile strength (UTS) were observed for the surface of samples rolled at 900 degrees C and 1100 degrees C, while the UTS values along the thickness direction did not differ much for samples rolled at 1000 degrees C. A significant deviation in total elongation was observed for the surface sample. Strain hardening exponent (n), strength coefficient (K), and strain hardening rate (theta) were considered to study the difference in tensile behavior. The through-thickness tensile properties were correlated to the microstructure and texture, which played an important role in the behavior.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Xin Hu, Chen Chen, Yanguo Li, Zhinan Yang, Fucheng Zhang, Wei Zhang
Summary: This study systematically investigated the microstructure evolution of 7Mo-0.42N contained cast super austenitic stainless steel (SASS) during compression deformation at high temperature. The recrystallization behavior of SASS was found to occur in three stages, and various phenomena such as grain refinement, abnormal growth, and dislocation evolution were observed. Additionally, the nucleation mechanism was found to change with different strain variables.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Robert Wonneberger, Gloria Kirste, Martin Seyring, Martin Hafermann, Carsten Ronning, Maximilian Schaal, Felix Otto, Torsten Fritz, Andreas Undisz
Summary: Understanding the growth mechanism of oxide layer on 316 L requires knowledge of reaction front position, oxide phase formation, and elements diffusion paths. By using Mn as a tracer in a new experimental approach, essential information of the early stages of oxidation up to 600 °C is obtained. The study suggests a previously undocumented role of Cr valence state during oxide growth, as Cr6+ is detected at 600 °C.