Article
Materials Science, Multidisciplinary
Yan Liu, Jinshan Li, Bin Tang, William Yi Wang, Minjie Lai, Lei Zhu, Hongchao Kou
Summary: In this study, the formation mechanism of gamma twins in TiAl alloys was analyzed at the atomic scale using HADDF-STEM. The results revealed the process of growth defects in alpha(2)-platelets transforming into the gamma phase, as well as the rearrangement of defects into gamma and gamma(T) platelets during annealing. This provides significant insights for microstructure control and performance improvement in TiAl alloys.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Michael Musi, Benjamin Galy, Jean-Philippe Monchoux, Alain Couret, Helmut Clemens, Svea Mayer
Summary: Electromagnetic-assisted sintering offers time-efficient densification for intermetallic gamma-TiAl based powders, with controlled microstructure and mechanical properties through imposed temperature profiles. This study presents insights into phase evolution during the process using high-energy X-ray diffraction, highlighting the transferability of data to spark plasma sintering technology. The experiment provides time-resolved observations of non-equilibrium and equilibrium phase transformations, showcasing the potential for electromagnetic-assisted sintering in powder consolidation processes.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Yonghao Yu, Hongchao Kou, Yichao Wang, Mengyu Jia, Xiaoxuan Xu, Zilong Zhang, Yarong Wang, Jinshan Li
Summary: Understanding the phase evolution is crucial for controlling microstructure and material performance. TiAl alloys with lightweight and elevated temperature properties are suitable for high-temperature applications. However, improving the microstructure and properties of TiAl alloys through hot working is challenging due to the difficulty in breaking up the lamellar colonies in the original microstructure. This study proposes a method for complete fragmentation of the lamellar structure in beta-solidified TiAl alloys by introducing a core-shell-like structure before hot working.
Article
Engineering, Manufacturing
Danni Huang, Qiyang Tan, Yinghao Zhou, Yu Yin, Feng Wang, Tao Wu, Xianliang Yang, Zhiqi Fan, Yingang Liu, Jingqi Zhang, Han Huang, Ming Yan, Ming-Xing Zhang
Summary: LaB6 nanoparticles were identified as an effective inoculant for LAMed gamma-TiAl alloy, leading to significantly reduced grain size and transformed microstructural morphology. The inoculation treatment not only resulted in crack-free alloy fabrication but also increased compressive yield strength, ultimate strength, and strain to fracture, showing comparable or even better performance than conventionally processed gamma-TiAl alloys.
ADDITIVE MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
Jieren Yang, Zitong Gao, Yongfeng Liang, Yulun Wu, Jinguang Li, Rui Hu
Summary: Fine-grained nearly-lamellar (FGNL) microstructures and ultrafine alpha(2)/gamma lamellar microstructures were successfully obtained by means of alpha-recrystallization in a Tie48Ale2Nb e2Cr alloy. The microstructure refinement is governed by small-strain alpha-deformation, with dominating continuous dynamic recrystallization (CDRX) responsible for lamellar grain refinement.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Materials Science, Multidisciplinary
Yong Xu, Yongfeng Liang, Lin Song, Guojian Hao, Bin Tian, Rongfu Xu, Junpin Lin
Summary: The experimental determination of the 8Nb isopleth section of the Ti-Al-Nb system reveals deviations from the calculated thermodynamic results, with the ordered beta(o) phase transforming from the disordered beta/alpha phases over a large Al concentration range, and the omega(o) phase transforming from the highly ordered beta(o) phase. The transition of the omega(o) phase from the beta(o) phase is considered to be a further ordering process based on experimental detection.
Article
Materials Science, Multidisciplinary
Jie Liu, Tongli Wu, Mengfei Wang, Li Wang, Qi Zhou, Kehong Wang, Peter Staron, Norbert Schell, Norbert Huber, Nikolai Kashaev
Summary: For the first time, this study conducted in situ observation of the grain refinement mechanism in TiAl alloys under high temperature conditions using synchrotron X-ray diffraction. The results showed a significant reduction in volume fraction and size of borides in the welding zone, with non-Burgers alpha grains nucleating earlier and Burgers alpha grains growing faster during the beta -> alpha transformation process.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Cheng-ren Dai, Zhi-biao Yang, Jian Sun, Song Lu, Levente Vitos
Summary: This paper investigates the decomposition process of the alpha(2) phase into the nano-sized orthorhombic (O) phase and blocky omega(0) phase in high Nb-containing γ-TiAl alloys at different temperatures. The study reveals that the transformation of O phase is controlled by Nb diffusion, while the formation of omega(0) phase is also related to Nb element. The pseudo-binary phase diagram accurately predicts the phase transformations in the alloys, providing insights for designing high Nb-containing γ-TiAl alloys.
Article
Materials Science, Multidisciplinary
Zhenquan Liang, Shulong Xiao, Qingchao Li, Xinyi Li, Dazhao Chi, Yunfei Zheng, Lijuan Xu, Xiang Xue, Jing Tian, Yuyong Chen
Summary: A creep-resistant Ti-45Al-6Nb-2.5V-0.15Y2O3 alloy was studied at different creep stages. It was found that the creep deformation of this alloy is influenced by dislocation slip, climb of gamma phase, and alpha 2 phase due to the activation of a slip system. The interactions among dislocation, twin boundary, and Y2O3 particle cause creep hardening, while dynamic recrystallization softens the alloy. Surface and bulk damage caused by oxidation and void nucleation increase the creep rate until fracture. Additionally, TiAl2 phases nucleate and grow during creep, maintaining a small planar disregistry with the gamma matrix.
MATERIALS CHARACTERIZATION
(2023)
Article
Chemistry, Physical
Ali Shaaban, Hirotoyo Nakashima, Mitsutoshi Ueda, Masao Takeyama
Summary: This study investigated the effects of oxygen addition on TiAl alloys at 1023 K, finding that it stabilized the alpha phase, reduced oxidation mass gains, and altered microstructure and phase transformations without significantly affecting oxidation resistance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
O. Ouadah, G. Merad, H. Si Abdelkader
Summary: In this study, first-principles methodology was used to analyze the impact of dilute solutes that segregate at the interface of gamma-TiAl and alpha(2)-Ti3Al. It was found that different solutes have varied effects on interface energy and stability, with Re being beneficial for enhancing the ductility of α(2)-Ti3Al.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Chemistry, Physical
Ali Shaaban, Loris J. Signori, Hirotoyo Nakashima, Masao Takeyama
Summary: The experimental study investigated the effects of transition metals on phase transformations in TiAl systems with different Al compositions at temperatures between 1473 and 1073 K. Microstructure evolutions and elemental compositions in different phases were examined, as well as the movements of the threephase tie triangle and changes of tie-lines at different temperatures to estimate the stability of alpha and alpha 2.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Review
Materials Science, Multidisciplinary
Michael Musi, Gloria Graf, Helmut Clemens, Petra Spoerk-Erdely
Summary: This review provides a detailed survey of the research work on the influence of technically important alloying elements on the Ti-Al phase diagram in γ-TiAl based alloys. After introducing the fundamentals of phase transformations, the alloying elements are discussed and their particularities are highlighted.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Zhenquan Liang, Shulong Xiao, Qingchao Li, Hongbao Yu, Yunfei Zheng, Lijuan Xu, Xiang Xue, Jing Tian, Yuyong Chen
Summary: The tensile creep behavior of a heat treated beta-solidified gamma-TiAl alloy was investigated at 800 degrees C and 250-300 MPa. The heat treatment improved the creep resistance of the alloy. Creep deformation is dominated by viscous dislocation glide and assisted by mechanical twinning. Twin boundary and TiB hinder dislocation movement and strengthen creep resistance. Dynamic recrystallization and B2 phase precipitation occur during creep. Creep voids prefer to nucleate at the gamma-B2 and B2-colony interfaces, leading to brittle-ductile mixed fracture.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Review
Chemistry, Physical
Ozge Genc, Rahmi Unal
Summary: Gamma titanium aluminides (γ-TiAl) are suitable for aerospace applications due to their high strength and low density at high temperatures. However, low ductility and fracture toughness at low temperatures limit their use. This study investigates the effect of additional alloying elements on improving the shortcomings of γ-TiAl alloy, resulting in improved microstructure and mechanical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
M. H. Abbasi, R. Tavakoli, S. G. Shabestari
Summary: The correlation between atomic-scale structure and glass-forming ability of ternary bulk metallic glasses was investigated using molecular dynamics simulation. It was found that the potential energy of the icosahedra reflects the geometric ordering, while the virial stress energy density reveals the chemical ordering. Based on this discovery, a new prediction criterion for glass-forming ability was proposed and validated using experimental data.
Article
Chemistry, Physical
Haimin Zhai, Shuai Cui, Sheng Li, Dongqing He, Bo Cheng, Xinjian Zhang, Wensheng Li, Zhornik Viktor, Uladzimir Seniuts
Summary: Laser shock peening (LSP) treatment significantly affects the phase structure and properties of titanium-based BMG materials, promoting rejuvenation and introducing heterogeneity. This leads to improved plasticity and resistance to crack propagation. LSP-1 specimen exhibits higher hardness and plasticity, reducing fatigue peeling wear caused by brittleness. However, excessive LSP results in increased susceptibility to pitting and significantly reduces tribocorrosion resistance.
Article
Chemistry, Physical
Olga A. Blatova, Maria A. Solodovnikova, Ekaterina M. Egorova, Vladislav A. Blatov
Summary: This study applied a universal geometrical-topological approach to analyze the crystal structures of intermetallic compounds deposited in the Inorganic Crystal Structure Database. By exploring the local atomic configurations, they identified different types of coordination polyhedra and proposed criteria for determining geometric instability. This research provides useful indicators for checking crystallographic information and validating structural models.
Article
Chemistry, Physical
Jose M. Torralba, Diego Iriarte, Damien Tourret, Alberto Meza
Summary: The amount of globally recycled e-waste is less than 20% of the total produced. One of the causes for this low recycling rate is the complex and expensive selective sorting of metals. However, recent research has shown that high entropy alloys (HEAs) can be made from complex alloy mixtures, reducing the dependence on pure critical metals. It has been demonstrated that e-waste can be used to produce competitive HEAs.
Article
Chemistry, Physical
M. Y. He, Y. F. Shen, N. Jia, W. Y. Xue, J. P. Li
Summary: This study successfully improved the mechanical properties of high-entropy alloys (HEAs) through phase decomposition modulation, achieving strengthening of low-cost CuFeMnNi HEAs. The annealed HEAs exhibited excellent mechanical properties, with significantly increased yield strength and maintained satisfactory elongation.
Article
Chemistry, Physical
D. V. Louzguine-Luzgin, F. R. Pratama
Summary: In this study, the growth rate of a crystalline phase in the Al-Fe-Mn-Si metallic glass was measured in real time using transmission electron microscopy. The effective diffusion coefficient related to the slowest diffusing element (Mn) was estimated. The results showed that the growth rate of the crystalline phase was significantly faster compared to pure Al and AlFe compound.
Article
Chemistry, Physical
Zhenhua Han, Yubo Tian, Jun Yang, Jianzhao Li, Jinyang Zhang, Gang Liu, Ran Wei, Guojun Zhang
Summary: In this study, a novel medium-entropy alloy (MEA) (Fe65Ni15Cr10Co10)92Ti5Al3 with a dual heterogeneous structure was developed by adding Ti and Al to a previously reported Fe65Ni15Co10Cr10 MEA. The MEA exhibited ultra-high ultimate tensile strength and work hardening extent at room temperature. The addition of Ti and Al induced precipitation and resulted in a continuous FCC -> BCC martensitic transformation and a transformation-induced plasticity effect. The excellent mechanical properties of the alloy were attributed to the synergistic effects of hetero-deformation induced strengthening, precipitation strengthening, and TRIP.
Article
Chemistry, Physical
S. Y. Liang, L. T. Zhang, B. Wang, Y. J. Wang, E. Pineda, J. C. Qiao
Summary: This study focuses on the influence of the thermomechanical protocol on the aging or rejuvenation of glass by decoupling the thermal and mechanical processes. The results show that Labased metallic glass exhibits material hypomnesia, with a clearer rejuvenation trend observed after imposing increasing amplitude strain oscillations. There is a threshold value of the oscillation amplitude that separates the effects of the protocol into acceleration of aging or rejuvenation. This study reveals the correlation between the thermomechanical properties of metallic glass and the previous application of strain oscillations of various amplitudes, providing an effective tool for regulating the structural state of metallic glasses through a simple-operated method.
Article
Chemistry, Physical
Chihui Liu, Hua Zhang, Qing Wang, Panzhi Wang, Jiadian Yang, Fanchao Meng, Xin Zhou, Lilong Zhu, Shangzhou Zhang, Liang Jiang
Summary: Thermal deformation behavior and microstructure evolution of GH141 alloy were efficiently studied using high-throughput double-cone gradient compression. Different compression temperatures resulted in a wide gradient equivalent strain distribution and gradient microstructure. The dynamic recrystallization mechanism shifted towards discontinuous dynamic recrystallization with increasing compression temperature.
Article
Chemistry, Physical
D. Dubaux, J. Zollinger, M. -C. de Weerd, J. Ghanbaja, S. Mathieu, S. Migot, P. Boulet, S. Sturm, V. Fournee, M. Sicot, J. Ledieu
Summary: We report the formation of large and highly twinned dendrites of the Al13Fe4 approximant phase embedded in an fcc Al-rich matrix. Using a rapid cooling technique, the approximant appears as a 10-fold dendrite. The grain distributions within the arm are complex and a single dendrite arm can contain up to four different orientations. Three types of twins, namely {100}, {001} and {201} twins, have been identified. A growth mechanism involving heteroepitaxial growth from a decagonal Al-Fe quasicrystalline seed is proposed to explain the formation of these specific 10-fold motifs.
Article
Chemistry, Physical
Ming Yang, Yibo Zhang, Jie Dong, Yan Huang, Zhichao Lu, Liang Wang, Xuerui Wei, Zhengdong Fu, Jinkui Zhao, Wenli Song, Wei Li, Yuntao Liu, Dong Ma
Summary: A multi-element microalloying strategy has been used to improve the microstructure and mechanical properties of CuZr-based bulk metallic glass composites. Microalloying effectively refines the CuZr phase and results in finely dispersed B2 crystallites embedded in the BMG matrix, leading to the formation of centimeter-sized BMGCs with good mechanical properties.
Article
Chemistry, Physical
Xuejie Zhu, Xuexi Zhang, Mingfang Qian, Ziyi Wang, Aibin Li, Zongning Chen, Muhammad Imran, Lin Geng
Summary: The homogeneous superelastic behavior in shape memory alloys (SMAs) is crucial for their functional and structural fatigue properties, as well as their stable elastocaloric effect (eCE). In this study, a Ti-22Nb-4Zr-2Ta plate was prepared with a strong recrystallized texture, resulting in a completely recoverable superelastic strain and narrow hysteresis. The observation of strain and temperature evolution revealed the importance of diffuse transformation and favorable texture in achieving mesoscopically homogeneous transformation and related elastocaloric effect.
Article
Chemistry, Physical
Mohammad Navazani, Sitarama Raju Kada, Daniel Fabijanic, Matthew Barnett
Summary: This study investigates the effect of Cu and Al addition on an alloy containing multiple principal elements. The results show that adding small amounts of Cu can improve the alloy's ductility and the hardness of the FCC phase can be predicted using a hybrid model. Unlike previous studies, the corrosion resistance of the alloy is not affected by Cu addition, indicating its potential for further development into a fine-grained stainless steel alloy.
Article
Chemistry, Physical
Fatemeh Azizian, Homam Naffakh-Moosavy, Fatemeh Bagheri
Summary: Novel biodegradable Zn-xCu-0.8Mn-0.4Ag alloys were prepared in this study, and the effects of Cu addition and hot extrusion process on microstructure, mechanical properties, and cytotoxicity of the alloys were investigated. The results showed that adding copper and performing a hot extrusion process can significantly improve the mechanical properties of the alloys, making them potential candidates for cardiovascular stents.
Article
Chemistry, Physical
Ivan A. Ditenberg, Denis A. Osipov, Ivan Smirnov, Konstantin V. Grinyaev
Summary: This study investigates the effect of high-temperature annealing on the structural-phase state and microhardness of Ni3Al samples obtained by spark plasma sintering after high-energy ball milling. The results show that certain annealing temperatures promote grain growth and high-density nucleation, leading to the formation of a fine-grained structural state. The study also analyzes the influence of annealing temperature on the strengthening mechanisms.