Article
Materials Science, Multidisciplinary
Yoon-Oh Jung, Min-Sik Kim, Jisung Park, Guang Yang, Dong Won Lee, Seong-Woong Kim
Summary: An improved step heat treatment method was developed to refine the microstructure of a cast TiAl alloy without hot working. The phase transformation behavior was identified and the heat treatment temperature and process were determined through a pseudo-phase diagram. The as-cast structure was eliminated through homogenization heat treatment before the heat treatment of each phase in the (alpha + gamma) region. Nucleation mainly occurred at the grain boundaries and the lamellar structure thickened during the (alpha + gamma) heat treatment. The step heat treatment effectively controlled the microstructure and improved the mechanical properties of the cast TiAl alloy at high temperatures.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Nitish Bibhanshu, Satyam Suwas
Summary: This study focused on modifying the lamellar microstructure of a gamma - TiAl alloy to a globular structure related to the alpha(2) phase through cyclic heat treatment. The thermal cycles led to the transformation of the lamellar alpha(2) phase to a globular structure. With increasing globularisation time, the average micro-hardness decreased along with grain coarsening. Additionally, the phase percentage of both phases stabilized with cycling time. Based on the phenomena of globularisation over time, a possible mechanism was proposed to understand the process.
Article
Materials Science, Multidisciplinary
Jan E. Schnabel, Ingo Scheider
Summary: The crystal plasticity model presented in this study offers a comprehensive understanding of the creep behavior of alloys with lamellar microstructures, by considering the competition between slip systems and recovery, and modeling the evolving dislocation density. This model is not limited to TiAl alloys and can also be applied to other crystalline materials with lamellar microstructures for studying their creep behavior.
FRONTIERS IN MATERIALS
(2021)
Article
Chemistry, Physical
Ji Young Kim, Eun Soo Park, Taegu Lee, Seunghwa Ryu, Seung-Eon Kim, Seong-Woong Kim
Summary: The study investigated the effect of tensile loading direction and additional elements on the deformation mechanisms of TiAl alloys, revealing that enhanced room temperature ductility can be achieved with the addition of Nb.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Metallurgy & Metallurgical Engineering
Xue-yi Guo, Zhao-wang Dong, Yang Xia, Pei-dong Liu, Han-ning Liu, Qing-hua Tian
Summary: A high-purity Ti-48Al-2Nb-2Cr alloy powder with low oxygen content and small particle size was successfully produced through reduction with magnesium and deoxidation with calcium. The phase and composition analysis showed that the product mainly consisted of gamma-TiAl and minor alpha(2)-Ti3Al phases, with Ti, Al, Cr, and Nb homogenously distributed in the powder.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2022)
Review
Chemistry, Physical
Anna Knaislova, Pavel Novak, Marcello Cabibbo, Lucyna Jaworska, Dalibor Vojtech
Summary: This paper discusses the influence of silicon on the manufacturing process, structure, phase composition, and properties of titanium aluminide alloys. TiAl-Si alloys are composed of a titanium aluminide matrix reinforced by titanium silicides, exhibiting wear resistance comparable to tool steels, high hardness, and good high-temperature oxidation resistance (up to 1000 degrees C), but low room-temperature ductility typical of intermetallic materials. The alloys have been successfully produced using powder metallurgical and melting metallurgy methods.
Article
Materials Science, Multidisciplinary
Lu Li, Guodong Ma, Haiguang Huang, Han Xiao, Zhentao Yuan, Yongkun Li, Rongfeng Zhou
Summary: This study investigated the flow behavior and instability prediction of the TA10 titanium alloy during isothermal compression, revealing flow softening mechanisms and instability criteria under different deformation temperatures. Suitable processing parameters were proposed based on microstructural analysis and flow stress-strain curves.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
Runrun Xu, Miaoquan Li
Summary: This study utilized transmission electron microscopy to investigate the hot deformation behavior of a beta-solidifying gamma-TiAl alloy with a duplex structure. It found that twinning is closely linked to twin intersections in gamma grains. As isothermal compression proceeded, faults evolved into twins, with dislocations aiding in promoting twinning in gamma grains.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Hariprasath Ganesan, Ingo Scheider, Christian J. Cyron
Summary: Gamma-titanium aluminide (TiAl) alloys with fully lamellar microstructure exhibit excellent properties for high-temperature applications. Molecular dynamics simulations were conducted to study the high-temperature separation behavior of different lamellar interfaces in TiAl. The simulation results revealed varying yield strength and failure behavior at different interfaces, providing important data for defining parameters in continuum mechanical modeling of TiAl.
FRONTIERS IN MATERIALS
(2021)
Article
Engineering, Manufacturing
Wenlu Zhou, Chen Shen, Xueming Hua, Lin Wang, Yuelong Zhang, Fang Li, Jianwen Xin, Yuhan Ding
Summary: In recent years, there has been increasing interest in additive manufacturing of titanium aluminide. Element additions have been a concern in order to improve the microstructure and mechanical properties of additively manufactured titanium aluminide. This study successfully introduced vanadium into gamma-TiAl alloy using the twin-wire directed energy deposition-arc (TW-DED-arc) method, aiming to enhance the strength and plasticity of the deposited TiAl component. The research investigated the microstructure, chemical composition homogeneity, and mechanical properties of TW-DED-arc deposited Ti-48Al and Ti-48Al-2V alloys, and found that vanadium additions improved the properties of the alloy.
ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Xuchen Jin, Peihao Ye, Wenbin Fang, Wei Sun, Zhuanxia Suo, Boxin Wei, Xuewen Li
Summary: The layered porous high Nb-TiAl alloys were prepared by vacuum hot-pressing sintering and multi-step heat treatment, showing better thermal insulation performance compared to traditional alloys at high temperatures.
Article
Materials Science, Multidisciplinary
Anupam Neogi, Rebecca Janisch
Summary: Strengthening of metals by incorporating nano-scale coherent twin boundaries has been a significant breakthrough in recent years. In this study, the contribution of twin boundaries in nano-lamellar lightweight Ti-Al alloys to deformation and fracture behavior is investigated using atomistic simulations. The results show that nano-scale lamellae effectively improve fracture toughness and crack growth resistance, and the lamellar size controls the crack tip mechanisms. A critical lamella thickness is identified, and above this thickness, crack tip events are primarily dislocation-based plasticity. Below the critical thickness, a decline in fracture toughness is observed and the crack tip propagation mechanisms become quasi-brittle in nature.
Article
Materials Science, Multidisciplinary
Chengren Dai, Jian Sun
Summary: The microstructure and room-temperature tensile property of the gamma-Ti-45Al-8.5Nb-(W, B, Y) alloy after different heat treatments were investigated. The results showed that different cooling methods could obtain different microstructures, and the alloy subjected to a two-step heat treatment showed improved tensile properties. The improved tensile properties were attributed to microstructure refinement and reduction of remnant B2 phase.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
Manoj Kumar Yadav, Arshad Noor Siddiquee, Zahid A. Khan
Summary: By utilizing mechanical alloying, Al60Ti40 alloy was successfully prepared with refined crystallite size and new AlTi alloyed phase. After 60 hours of milling, the average particle size reduced around seven times, and the mean crystallite size decreased to approximately 85 nm.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Engineering, Mechanical
Arthur Lintner, Reinhard Pippan, Martin Schloffer, Anton Hohenwarter
Summary: This study analyzed the effect of single overloads on the threshold of stress intensity range of a semi-brittle material and found a significant increase in the slope of the R-curve.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
D. Bombac, I. H. Katzarov, D. L. Pashov, A. T. Paxton
MATERIALS SCIENCE AND TECHNOLOGY
(2017)
Article
Physics, Multidisciplinary
Bingqing Cheng, Anthony T. Paxton, Michele Ceriotti
PHYSICAL REVIEW LETTERS
(2018)
Article
Materials Science, Multidisciplinary
Bartosz Barzdajn, Anthony T. Paxton, David Stewart, Fionn P. E. Dunne
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2018)
Article
Materials Science, Multidisciplinary
E. Andritsos, A. T. Paxton
PHYSICAL REVIEW MATERIALS
(2019)
Article
Materials Science, Multidisciplinary
Luca Cimbaro, Adrian P. Sutton, Daniel S. Balint, Anthony T. Paxton, Mark C. Hardy
INTERNATIONAL JOURNAL OF FRACTURE
(2019)
Article
Chemistry, Physical
Sebastian Echeverri Restrepo, Davide Di Stefano, Matous Mrovec, Anthony T. Paxton
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2020)
Article
Materials Science, Multidisciplinary
Haiyang Yu, Ivaylo H. Katzarov, Anthony T. Paxton, Alan C. F. Cocks, Edmund Tarleton
PHYSICAL REVIEW MATERIALS
(2020)
Article
Multidisciplinary Sciences
Peng Gong, Ivaylo H. Katzarov, John Nutter, Anthony T. Paxton, W. Mark Rainforth
SCIENTIFIC REPORTS
(2020)
Article
Nanoscience & Nanotechnology
Peng Gong, Ivaylo Katzarov, John Nutter, Anthony T. Paxton, Bradley Wynne, W. Mark Rainforth
Summary: This study investigated the influence of hydrogen on dislocation mobility in pure single crystal iron through experiments and simulations. Hydrogen charging altered the nanoindentation load curve and distribution of dislocations in the material.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
I. H. Katzarov, L. B. Drenchev, D. L. Pashov, T. N. A. T. Zarrouk, O. Al-lahham, A. T. Paxton
Summary: This study develops an atomistic kinetic Monte Carlo (kMC) model to describe carbon diffusion, trapping and detrapping in the stress field generated by a 1/2[111] screw dislocation in bcc iron. The kMC simulations predict the rate of formation and strength of carbon atmospheres, which control the behavior of the dislocation and result in dynamic strain aging in steel. Pipe diffusion within the dislocation core dominates the effective diffusivity, except at low carbon concentrations. The kMC approach provides an atomistic view of the carbon drag mechanism by which mobile dislocations collect and transport carbon.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Sebastian Echeverri Restrepo, Predrag Andric, Anthony T. Paxton
Summary: We propose a general scheme for simulating the diffusion of interstitial solutes in metals with modified diffusivity due to the presence of defects. By using classical interatomic potentials and molecular dynamics, we calculate the diffusivity of carbon in iron and investigate the effects of substitutional alloying elements and edge dislocations.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Multidisciplinary Sciences
Martina Ruffino, John Nutter, Xun Zeng, Dikai Guan, W. Mark Rainforth, Anthony T. Paxton
Summary: This study presents a model based on twinning disconnections to investigate the faceting phenomenon in single, double, and triple twin boundaries in magnesium. The theoretical predictions of commensurate facets in single and double twin boundaries are validated by transmission electron microscopy observations of a Mg-1.18wt%Al-1.77wt%Nd alloy with single, double, and rare triple twins. The study discusses the influence of facets on the macroscopic orientation of twin interfaces.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Martina Ruffino, Guy C. G. Skinner, Eleftherios I. Andritsos, Anthony T. Paxton
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2020)
Article
Materials Science, Multidisciplinary
Sebastian Echeverri Restrepo, Henry Lambert, Anthony T. Paxton
PHYSICAL REVIEW MATERIALS
(2020)
Article
Materials Science, Multidisciplinary
Guy C. G. Skinner, Anthony T. Paxton, John A. Moriarty