Article
Materials Science, Multidisciplinary
Dong Huang, Yanxin Zhuang
Summary: In this study, the coherent precipitation strengthening of L1(2) phase and Face-Centered Cubic (FCC) -Hexagonal Close-Packed (HCP) type martensitic transformation were successfully combined in a single alloy, resulting in increased yield strength and uniform elongation. The presence of L1(2) phase was found to directly affect the deformation mode of the alloy.
MATERIALS & DESIGN
(2022)
Article
Materials Science, Multidisciplinary
R. E. Kubilay, W. A. Curtin
Summary: This study investigates the mechanism of twinning in fcc High Entropy Alloys (HEAs) and its impact on strength, proposing a twinning stress theory and validating it through experiments. The results indicate that twinning is controlled by twin nucleation in fcc alloys.
Article
Materials Science, Multidisciplinary
Wei Zhang, Zhichao Ma, Chaofan Li, Chaowei Guo, Dongni Liu, Hongwei Zhao, Luquan Ren
Summary: A systematic investigation was conducted to study the interphase strengthening effects on the mechanical performances of multiphase high-entropy alloys (HEAs) at micro/nano-scale compared with single phase HEAs. The study revealed that the interphase exhibited significantly higher strength compared to other phases, and the mechanical size effects were independent of the phase type.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Materials Science, Coatings & Films
Maya K. Kini, Subin Lee, Alan Savan, Benjamin Breitbach, Younes Addab, Wenjun Lu, Matteo Ghidelli, Alfred Ludwig, Nathalie Bozzolo, Christina Scheu, Dominique Chatain, Gerhard Dehm
Summary: The study extensively examines the phase evolution of bulk quaternary equiatomic CoCrFeNi alloy, finding that nanocrystalline alloys in thin film state exhibit accelerated kinetics of phase and microstructure evolution, and that second phases can form even at room temperature when there are sufficient nucleation sites.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Nanoscience & Nanotechnology
Tanner Kirk, Brent Vela, Seth Mehalic, Khaled Youseff, Raymundo Arroyave
Summary: High Entropy Alloys (HEAs) are an important alloy design paradigm, where chemical complexity can stabilize single-phase alloys relative to other solid phases, but may also lead to instability against the liquid phase. This study conducted a comprehensive investigation of phase stability in the fcc CoCrFeMnNiV-Al HEA space using a state-of-the-art CALPHAD database, revealing a trade-off between chemical complexity and stability.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
S. I. Rao, C. Woodward, B. Akdim, O. N. Senkov, D. Miracle
Summary: An analytic model for substitutional solid solution strengthening in BCC CCAs based on a/2<111> screw dislocation mobility is developed and presented. Different strengthening mechanisms are observed at different temperatures, requiring modifications to existing models to apply to refractory CCAs.
Article
Chemistry, Physical
Diaa Mereib, Judith Monnier, Loic Perriere, Benjamin Villeroy, Mathilde Laurent-Brocq
Summary: Chemically architectured alloys are a new concept of microstructure, where the strengthening effect is induced by a 3D network of composition fluctuations called interphase. The width and volume fraction of the interphase can be controlled by processing parameters, such as sintering temperature and applied pressure. This study demonstrates that chemically architectured alloys can achieve efficient and tunable strengthening by optimizing the microstructure.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Abhishek Mehta, Yongho Sohn
Summary: Experimental measurements of chemical and tracer diffusion coefficients in Al0.25CoCrFeNi high-entropy alloy suggest that diffusion may not necessarily be sluggish, indicating a more complex diffusion behavior in high-entropy alloys than previously thought.
MATERIALS RESEARCH LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Ryoji Katsube, Litian Luo, Keita Nakano, Taka Narumi, Hideyuki Yasuda
Summary: The solidification sequence of the CrMnFeCoCu alloy, a multicomponent and multiphase alloy derived from the CrMnFeCoNi alloy, was investigated. It was found that the microstructure of this alloy formed through a process of liquid-liquid phase separation and subsequent solid-phase transformation, rather than the conventional multiphase solidification manner. The understanding of these processes can contribute to the control of microstructure in multicomponent and multiphase alloys.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Tasneem Z. Khan, Tanner Kirk, Guillermo Vazquez, Prashant Singh, A. Smirnov, Duane D. Johnson, Khaled Youssef, Raymundo Arroyave
Summary: Stacking Fault Energy (SFE), an intrinsic property of alloys, plays a crucial role in governing the plastic deformation mechanisms in fcc alloys. In this study, a combination of DFT calculations, machine learning, and physics-based models is utilized to predict the SFE in the high-entropy alloy space. The developed model accurately predicts the SFE of arbitrary compositions and enables the exploration of new alloys with interesting mechanical behavior.
Article
Materials Science, Multidisciplinary
Y. Rao, W. A. Curtin
Summary: In this study, a statistical-mechanics analysis is used to estimate the short-range order (SRO) parameters in solid solution alloys. The analysis assumes pair interactions among atoms at different distances and treats the crystal as a set of independent clusters. The results allow for a fast assessment of likely SRO using estimated or computed inputs for atom-atom interaction energies.
Article
Materials Science, Multidisciplinary
Huixin Liu, Changfa Du, Yuling Liu, Shiyi Wen, Qianhui Min, Jieqiong Hu, Ming Xie, Yong Du
Summary: The diffusivities and atomic mobilities of fcc Co-Cu-Mn alloys were investigated to provide key inputs for the computational design of high-entropy alloys. Diffusivities were determined through experimental diffusion couples, and atomic mobilities were extracted accordingly. The numerical inverse approach showed higher efficiency and provided more composition-dependent diffusivities and reliable atomic mobilities compared to the traditional Matano-Kirkaldy method.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Physical
Lili Ma, Jianing Wang, Zhangheng Lai, Zhichao Wu, Baiting Yang, Panpan Zhao
Summary: A series of Fe-free Al56-xCo24Cr20Nix (x = 34, 36, 38, 40, and 42) eutectic high-entropy alloys were designed and prepared to study the influence of Al and Ni content on microstructure and mechanical properties. The results revealed that all the alloys exhibited a typical eutectic microstructure and an ordered FCC/BCT phase structure. Increasing Ni content led to a reduction in the volume fraction of the BCT phase. The Ni38 alloy showed an unsatisfactory tensile property due to irregular eutectic lamellas, while the Ni38.5 alloy with a regularly and fine lamellar hypereutectic microstructure exhibited improved fracture strain without compromising yield strength.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Applied
Liang Wang, Xudong Liu, Chunxi Li, Minzheng Yang, Benpeng Wang, Kaisheng Ming, Shijian Zheng, Jun Liang, Yunfei Xue
Summary: Designing a new type of metastable refractory high entropy alloy with transformation induced plasticity effectively addressed the issue of low ductility. The alloy exhibited remarkable ductility and demonstrated good deformability during tension deformation. Through analyzing the variation of lattice distortion, it was believed that the FCC martensite was generated by relaxing the lattice distortion.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Kaisheng Zhang, Xinghua Zhang, Engui Zhang, Ran Wei, Lilin Wang, Junli Chen, Shuhan Yuan, Zhenhua Han, Chen Chen, Fushan Li
Summary: The study focuses on designing a cost-effective Fe65Co10Ni10Cr15 medium-entropy alloy with excellent cryogenic strength of 1.6 GPa and a strain of 56%, demonstrating the highest strength-price ratio among reported MEAs. The alloy's significant strengthening is attributed to hetero-deformation and accelerated deformation-induced phase transformation.
Article
Materials Science, Multidisciplinary
Y. Liu, K. Zweiacker, C. Liu, J. T. McKeown, J. M. K. Wiezorek
Summary: The evolution of rapid solidification microstructure and solidification interface velocity of hypereutectic Al-20at.%Cu alloy after laser melting has been studied experimentally. It was found that the formation of microstructure was dominated by eutectic, alpha-cell, and banded morphology grains, and the growth modes changed with increasing interface velocity.
Article
Materials Science, Multidisciplinary
Bharat Gwalani, Julian Escobar, Miao Song, Jonova Thomas, Joshua Silverstein, Andrew Chihpin Chuang, Dileep Singh, Michael P. Brady, Yukinori Yamamoto, Thomas R. Watkins, Arun Devaraj
Summary: Castable alumina forming austenitic alloys exhibit superior creep life and oxidation resistance at high temperatures. This study reveals the mechanism behind the enhanced creep performance of these alloys by suppressing primary carbide formation and offers a promising alloy design strategy for high-temperature applications.
Article
Materials Science, Multidisciplinary
Jian Song, Qi Zhang, Songsong Yao, Kunming Yang, Houyu Ma, Jiamiao Ni, Boan Zhong, Yue Liu, Jian Wang, Tongxiang Fan
Summary: Recent studies have shown that achieving an atomically flat surface for metals can greatly improve their oxidation resistance and enhance their electronic-optical applications. Researchers have explored the use of graphene as a covering layer to achieve atomically flat surfaces. They found that high-temperature deposited graphene on copper surfaces formed mono-atomic steps, while annealed copper and transferred graphene on copper interfaces formed multi-atomic steps.
Article
Materials Science, Multidisciplinary
Jennifer A. Glerum, Jon-Erik Mogonye, David C. Dunand
Summary: Elemental powders of Al, Ti, Sc, and Zr are blended and processed via laser powder-bed fusion to create binary and ternary alloys. The microstructural analysis and mechanical testing show that the addition of Ti results in the formation of primary precipitates, while the addition of Sc and Zr leads to the formation of fine grain bands. The Al-0.25Ti-0.25Zr alloy exhibits comparable strain rates to Al-0.5Zr at low stresses, but significantly higher strain rates at higher stresses during compressive creep testing. Finite element modeling suggests that the connectivity of coarse and fine grain regions is a critical factor affecting the creep resistance of the alloys.
Article
Materials Science, Multidisciplinary
P. Jannotti, B. C. Hornbuckle, J. T. Lloyd, N. Lorenzo, M. Aniska, T. L. Luckenbaugh, A. J. Roberts, A. Giri, K. A. Darling
Summary: This work characterizes the thermo-mechanical behavior of bulk nanocrystalline Cu-Ta alloys under extreme conditions. The experiments reveal that the alloys exhibit unique mechanical properties, behaving differently from conventional nanocrystalline Cu. They do not undergo grain coarsening during extrusion and exhibit behavior similar to coarse-grained Cu.
Article
Materials Science, Multidisciplinary
Yiqing Wei, Jingwei Li, Daliang Zhang, Bin Zhang, Zizhen Zhou, Guang Han, Guoyu Wang, Carmelo Prestipino, Pierric Lemoine, Emmanuel Guilmeau, Xu Lu, Xiaoyuan Zhou
Summary: This study proposes a new strategy to modify microstructure by phase regulation, which can simultaneously enhance carrier mobility and reduce lattice thermal conductivity. The addition of Cu in layered SnSe2 induces a phase transition that leads to increased grain size and reduced stacking fault density, resulting in improved carrier mobility and lower lattice thermal conductivity.
Article
Materials Science, Multidisciplinary
Jia Chen, Zhengyu Zhang, Eitan Hershkovitz, Jonathan Poplawsky, Raja Shekar Bhupal Dandu, Chang-Yu Hung, Wenbo Wang, Yi Yao, Lin Li, Hongliang Xin, Honggyu Kim, Wenjun Cai
Summary: In this study, the structural origin of the pH-dependent repassivation mechanisms in multi-principal element alloys (MPEA) was investigated using surface characterization and computational simulations. It was found that selective oxidation in acidic to neutral solutions leads to enhanced nickel enrichment on the surface, resulting in reduced repassivation capability and corrosion resistance.
Article
Materials Science, Multidisciplinary
X. Y. Xu, C. P. Huang, H. Y. Wang, Y. Z. Li, M. X. Huang
Summary: The limited slip systems of magnesium (Mg) and its alloys hinder their wide applications. By conducting tensile straining experiments, researchers discovered a rate-dependent transition in the dislocation mechanisms of Mg alloys. At high strain rates, glissile dislocations dominate, while easy-glide dislocations dominate at low strain rates. Abundant glissile dislocations do not necessarily improve ductility.
Article
Materials Science, Multidisciplinary
M. S. Szczerba, M. J. Szczerba
Summary: Inverse temperature dependences of the detwinning stress were observed in face-centered cubic deformation twins in Cu-8at.%Al alloy. The detwinning stress increased with temperature when the pi detwinning mode was involved, but decreased when the pi/3 mode was involved. The dual effect of temperature on the detwinning stress was due to the reduction of internal stresses pre-existing within the deformation twins. The complete reduction of internal stresses at about 530 degrees C led to the equivalence of the critical stresses of different detwinning modes and a decrease in the yield stress anisotropy of the twin/matrix structure.
Article
Materials Science, Multidisciplinary
Taowen Dong, Tingting Qin, Wei Zhang, Yaowen Zhang, Zhuoran Feng, Yuxiang Gao, Zhongyu Pan, Zixiang Xia, Yan Wang, Chunming Yang, Peng Wang, Weitao Zheng
Summary: The interaction between the electrode and the electric double layer (EDL) significantly influences the energy storage mechanism. By studying the popular alpha-Fe2O3 electrode and the EDL interaction, we find that the energy storage mechanism of the electrode can be controlled by modulating the EDL.
Article
Materials Science, Multidisciplinary
Matthew R. Barnett, Jun Wang, Sitarama R. Kada, Alban de Vaucorbeil, Andrew Stevenson, Marc Fivel, Peter A. Lynch
Summary: The elastic-plastic transition in magnesium alloy Mg-4.5Zn exhibits bursts of deformation, which are characterized by sudden changes in grain orientation. These bursts occur in a coordinated manner among nearby grains, with the highest burst rate observed at the onset of full plasticity. The most significant burst events are associated with twinning, supported by the observation of twinned structures using electron microscopy. The bursts are often preceded and followed by a stasis in peak movement, indicating a certain "birth size" for twins upon formation and subsequent growth at a later stage.
Article
Materials Science, Multidisciplinary
Vaidehi Menon, Sambit Das, Vikram Gavini, Liang Qi
Summary: Understanding solute segregation thermodynamics is crucial for investigating grain boundary properties. The spectral approach and thermodynamic integration methods can be used to predict solute segregation behavior at grain boundaries and compare with experimental observations, thus aiding in alloy design and performance control.
Article
Materials Science, Multidisciplinary
Feiyu Qin, Lei Hu, Yingcai Zhu, Yuki Sakai, Shogo Kawaguchi, Akihiko Machida, Tetsu Watanuki, Yue-Wen Fang, Jun Sun, Xiangdong Ding, Masaki Azuma
Summary: This study reports on the negative and zero thermal expansion properties of Cd2Re2O7 and Cd1.95Ni0.05Re2O7 materials, along with their ultra-low thermal conductivity. Through investigations of their structures and phonon calculations, the synergistic effect of local structure distortion and soft phonons is revealed as the key to achieving these distinctive properties.
Article
Materials Science, Multidisciplinary
Thomas Beerli, Christian C. Roth, Dirk Mohr
Summary: A novel testing system for miniature specimens is designed to characterize the plastic response of materials for which conventional full-size specimens cannot be extracted. The system has an automated operation process, which reduces the damage to specimens caused by manual handling and improves the stability of the test results. The experiments show that the miniature specimens extracted from stainless steel and aluminum have high reproducibility, and the results are consistent with those of conventional-sized specimens. A correction procedure is provided to consider the influence of surface roughness and heat-affected zone caused by wire EDM.
Article
Materials Science, Multidisciplinary
Rani Mary Joy, Paulius Pobedinskas, Nina Baule, Shengyuan Bai, Daen Jannis, Nicolas Gauquelin, Marie-Amandine Pinault-Thaury, Francois Jomard, Kamatchi Jothiramalingam Sankaran, Rozita Rouzbahani, Fernando Lloret, Derese Desta, Jan D'Haen, Johan Verbeeck, Michael Frank Becker, Ken Haenen
Summary: This study investigates the influence of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond thin films. The results provide insights into the mechanical properties and intrinsic stress sources of these films, and demonstrate the potential for producing high-quality nanocrystalline diamond films under certain conditions.