Article
Engineering, Industrial
Tianle Li, Shu Yan, Dayong An, Xifeng Li, Jun Chen
Summary: By adjusting the initial delta-ferrite microstructure based on cold-rolling, two types of unusual austenite transformation were investigated in a medium-Mn steel during intercritical annealing. Firstly, an increase in delta/alpha' phase interfaces promotes gamma formation. Secondly, precipitation of carbide particles from delta phase in cold-rolled samples creates a condition for subsequent gamma nucleation.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
J. Joseph, M. Annasamy, P. Cizek, A. Vahid, P. D. Hodgson, M. R. Barnett, D. M. Fabijanic
Summary: A novel Fe-rich medium entropy alloy (MEA) space with a & gamma;+& gamma;'-only phase field at 800 degrees C is proposed where the volume fraction and dissolution temperature of & gamma;'-phase can be tuned by substituting Fe for Ni/Co and Cr. The Fe-35.5Ni-4Cr-6.3Al-3.2Ti alloy in the γ+γ'-structured form (Fe-content of 51 at.%; & gamma;'-volume fraction of 24%) exhibits a yield strength of 902 MPa, ultimate strength of 1370 MPa, and a tensile ductility of 24% after a recrystallisation and ageing treatment. This research contributes to the development of Fe-rich MEAs with good strength retention (>600 degrees C) for heat-resistant structural applications.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Shao-Bin Bai, Da-Zhao Li, Hui-Hu Lu, Wei-Qiang Niu, Wei Liang, Pei-Kang Bai, Zhi-Quan Huang
Summary: A novel strengthening strategy, warm rolling and intercritical annealing, was proposed to optimize the strength and ductility of a Fe-10.2 Mn-2.2Al-0.41C-0.6V (wt.%) steel. The strategy generated numerous microbands and nano-size VC particles in the warm-rolled samples, which activated the transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) effects. The synergistic effect of VC precipitates, microbands, dislocations, and TRIP and TWIP effects enhanced the ductility, tensile strength, and work hardening.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Yi-hao Luo, Wei-li Cheng, Hang Li, Hui Yu, Hong-xia Wang, Xiao-feng Niu, Li-fei Wang, Zhi-yong You, Hua Hou
Summary: A novel extruded Mg-5Bi-5Sn-1Mn alloy with bimodal microstructure is developed, showing high yield strength and ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Reza Ghiaasiaan, Nabeel Ahmad, Paul R. Gradl, Shuai Shao, Nima Shamsaei
Summary: This study compares the effects of different heat treatment temperatures on Haynes 282 and finds that even with larger gamma' precipitates, low temperature heat treatment can achieve comparable tensile properties to conventional heat treatment.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Wei Le, Zhongwei Chen, Kang Yan, Sufyan Naseem, Yanni Zhao, Haolan Zhang, Zhe Zhang
Summary: The early evolution of the delta phase and coarse gamma ' phase in aged Inconel 718 alloy was studied by transmission electron microscope. The needle-like delta phase first nucleates at the grain boundary and then grows into the grain interior. In addition, the coarse gamma ' phase nucleates at the dislocation, and the increase in size leads to the loss of coherence with the matrix, in which the strengthening effect is not obvious.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Bin Hu, Guohui Shen, Zheng Wang, Shilei Li, Yandong Wang, Haiwen Luo
Summary: We have developed a new type of ultrastrong medium Mn steel with a density reduced to 7.39 g cm-3. This steel has a unique tri-phase microstructure consisting of a hierarchical martensitic matrix, ultra-fine-retained austenite grains, and compressed and {200} oriented 8-ferrite lamellas. The high Al and Si contents in the alloying contribute to the formation of 8-ferrite lamellas and the reduction of density. Through in-situ synchrotron-based high-energy X-ray diffraction examinations, it is revealed that the residual compressive stress in 8-ferrite, dislocation multiplication in all three phases, and the gamma-to-alpha' transformation contribute to the remarkable work hardening increment. This study facilitates the development of novel strategies for fabricating ultrastrong but light steels.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Metallurgy & Metallurgical Engineering
Sun Yi, Zheng Qinyuan, Hu Baojia, Wang Ping, Zheng Chengwu, Li Dianzhong
Summary: This study aims to investigate the microstructural behavior of deformation-induced ferrite transformation (DIFT) in Medium Mn steels (MMSs) in order to understand the formation and post-deformation conservation of ultrafine ferrite. The results showed that DIFT occurs in the alpha+gamma region of thermomechanically processed MMSs, resulting in characteristic multiphase microstructures that consist of isolated martensite and fine-grained equiaxed ferrite with islands of retained austenite dispersed between ferrite grains. Enhanced ferrite nucleation at alpha/gamma interfaces during DIFT increases nucleation density and facilitates impingement among neighboring grains. The partitioning of Mn between ultrafine ferrite and austenite is accelerated during DIFT, leaving numerous Mn-enriched islands of austenite untransformed at grain boundaries or triple junctions, which play critical roles in retaining austenite at room temperature and conserving the ultrafine microstructure of DIFT during post-deformation processing.
ACTA METALLURGICA SINICA
(2022)
Article
Engineering, Mechanical
Zheng Wang, Zhongmin Wan, Xi Chen, Juanping Xu, Yao Zhou, Taiming Huang, Xiangzhong Kong, Changjie Ou, Jing Zhang, Jinxu Li
Summary: This research investigates the H-induced fracture behavior of Fe-6Mn-0.2C-3Al-0/0.6Si steels. The study found that the microstructure of the steels greatly affects the formation and propagation of HICs, and different planes exhibit different H-induced fracture behaviors.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Materials Science, Multidisciplinary
Li-bin Jin, Shu-guo Zheng, Miao-yong Zhu
Summary: The formation mechanism of AlN-MnS complex inclusions in Fe-5Mn-2Al-0.15C medium Mn steel under as-cast conditions was investigated through microstructure observation, thermodynamic analyses, and the Clyne-Kurz microsegregation model. The results showed that the variations in partition coefficients and diffusion coefficients of solute elements should be considered in the Clyne-Kurz model during the solidification process. The precipitation temperatures of AlN and MnS were determined as 1738 K and 1717 K, respectively, by the Clyne-Kurz model considering variable partition coefficients and diffusion coefficients.
Article
Materials Science, Multidisciplinary
Weitao Liu, Tong Han, Luling Wang, Binyin Zhu, Jianxin Jiang, Jianqiu Zhou
Summary: This paper quantitatively investigates the effect of Mn addition on the tensile behavior of ferritic/austenitic iron duplexes using molecular dynamics simulations. The results show that Mn can delay plastic deformation, increase dislocation density, and promote phase transformation to improve the strength and tensile properties of the material.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Materials Science, Multidisciplinary
Yao Lu, Li Liu, Jinkui Meng, Zhe Chen, Liang Zhen
Summary: This study proposes a new industry-friendly approach to develop lightweight yet high-performance medium Mn steel through partial austenitization. The medium Mn steel with partial austenitization exhibits a refined microstructure, particularly with heterogeneous microstructure of retained austenite in different sizes and morphologies. This multi-scale austenite enables a sustainable TRIP effect during deformation, achieving a superior strength-ductility combination up to 60 GPa.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Zhen-yu Guo, Wei-li Cheng, Hong-xia Wang, Hui Yu, Xiao-feng Niu, Li-fei Wang, Hang Li, Hua Hou
Summary: A novel low-alloyed Mg-2Sn-2Bi-0.2Mn alloy was successfully designed and extruded, demonstrating a good balance between strength and ductility. The bimodal-sized grain structure played a crucial role in achieving this balance, as analyzed in the study.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Tianle Li, Shu Yan, Xianghua Liu
Summary: This experiment systematically investigated the effects of annealing temperature on the microstructure evolution, mechanical properties, and deformation behaviors of cold-rolled Fe-0.05C-6Mn-1Al-1.5Si steel. Annealing at 740 degrees Celsius achieved an outstanding combination of strength and ductility due to the presence of ultrafine grains and optimal TRIP effect. Additionally, the phenomenon of yield point elongation shortening with increased gamma content and decreased gamma stability was observed.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Multidisciplinary Sciences
Chang-Yu Hung, Yu Bai, Tomotsugu Shimokawa, Nobuhiro Tsuji, Mitsuhiro Murayama
Summary: This study experimentally demonstrates the critical role of grain boundary characters in understanding the mechanism of deformation twin nucleation. Specifically, local stresses at particular boundaries, such as Sigma 3{111}, can trigger deformation twin nucleation. This finding highlights the practical importance of considering grain boundary characters in understanding material mechanical properties beyond established factors such as stacking fault energy and grain size.
SCIENTIFIC REPORTS
(2021)
