Article
Chemistry, Physical
Michael Musi, Helmut Clemens, Andreas Stark, Peter Staron, Petra Spoerk-Erdely
Summary: In this study, the effect of beta-stabilizing element molybdenum on the phase transitions in intermetallic gamma-TiAl based alloys is investigated. Different microstructures and phase transformations are observed in two model alloys with varying Mo content. The findings suggest that Mo significantly affects the stability and presence of the beta phase in these alloys. Additionally, long-term heat treatments reveal the phase equilibria at intermediate temperatures. The results from this work contribute to the reassessment of the quasi-binary phase diagram for Ti-44Al-(0-7)Mo (at.%).
Article
Materials Science, Multidisciplinary
Pedro Akira Bazaglia Kuroda, Marcos Ribeiro da Silva, Carlos Roberto Grandini
Summary: This study investigated the diffusion of oxygen in Ti-20Zr-7.5Mo and Ti-20Zr-10Mo alloys using mechanical spectroscopy measurements. The results showed that the peaks exhibited thermal activation, with a shift of Q(p)(-1) towards higher temperatures at high frequencies. The activation energy and diffusivity of oxygen in the alloys were obtained through mathematical analysis of the relaxation time derived structures.
Article
Chemistry, Physical
Xin Hu, Lin Qi, Chaoqiang Liu, Houwen Chen, Xiaoyong Zhang, Hongge Yan, Kechao Zhou, Min Song
Summary: In this study, stacking faults within alpha '' martensite plates were investigated using advanced transmission electron microscopy and first-principles calculations. Two kinds of stacking faults were detected, and their formation mechanism was explained. These findings provide important insights into the martensitic transformation process from bcc-beta to orthorhombic-alpha '' phase.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Ceramics
Cheng-Feng Du, Yaqing Xue, Qingyan Zeng, Jinjin Wang, Xiangyuan Zhao, Zjiao Wang, Chuanchao Wang, Hong Yu, Weimin Liu
Summary: In this study, Cr-Ti-Mo ternary o-MAX ceramics based on the Cr2TiAlC2 phase were synthesized and their tribological performance at high temperatures was evaluated. The results showed that Cr1.9Ti0.9Mo0.2AlC2 exhibited an unexpected ultra-low wear rate and stable coefficient of friction at 800 degrees C. XPS analysis confirmed the presence of a tribofilm with gradient composition, providing high-temperature lubrication and self-healing capabilities.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Nanoscience & Nanotechnology
Felicity F. Worsnop, Susannah L. M. Lea, Jan Ilavsky, David Rugg, David Dye
Summary: Increasing attention is being paid to alpha(2) Ti-3(Al,Sn) precipitation in jet engine titanium due to its impact on slip band formation, localization, and fatigue performance. However, observing the early stages of alpha(2) precipitation has been challenging using traditional methods. This study used small angle X-ray scattering to reexamine the phase boundary in Ti-Al and Ti-Sn alloys with O content, and found that the phase boundaries in the literature were approximately correct. The findings suggest that Al may be a more suitable solid solution strengthener than Sn for ambient temperature applications, but lower Al-eq limits should be considered for future alloy design.
SCRIPTA MATERIALIA
(2023)
Review
Materials Science, Multidisciplinary
Kunming Pan, Yanping Yang, Shizhong Wei, Honghui Wu, Zhili Dong, Yuan Wu, Shuize Wang, Laiqi Zhang, Junping Lin, Xinping Mao
Summary: Continuous exploration of high-temperature structural materials is driven by the needs of gas-turbine engines, with Mo-Si-B alloys as a new generation ultrahigh-temperature structural material, but oxidation remains a concern.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Physical
Yali Xu, Lingyu Xu, Liang Ding, Shuaifeng Zhang, Binbin Zhang, Hengpei Pan, Xiaoyang Lu, Peng Jiang
Summary: The microstructure and microtexture evolution of a near-alpha titanium alloy Ti-6321 during the post-annealing process were investigated. The results showed that the recrystallization, alpha grain globularization, coarsening, and phase transformation occurred, resulting in changes in macrozone sizes, morphologies, and texture components.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Shilin Feng, Xinghua Zhang, Ran Wei, Qiuyu Gao, Chen Chen, Tan Wang, Yongfu Cai, Fushan Li, Shaojie Wu
Summary: The addition of Ti and Mo significantly improves the yield strength and ductility of metastable dual-phase Fe60Cr15Ni16Al9 CCA. The obtained Fe60Cr15Ni16Al7Ti1Mo1 CCA exhibits excellent yield strength and ductility at low temperature.
Article
Chemistry, Physical
Ka-Kin Wong, Hsueh-Chuan Hsu, Shih-Ching Wu, Wen-Fu Ho
Summary: Three nonequiatomic Ti-rich Ti-Zr-Nb-Mo medium-entropy alloys were developed for biomedical applications, exhibiting high yield strength, low elastic moduli, and excellent resilience. The distortion effect caused by alloying atomic radius difference contributed to the superior yield strengths of the alloys. Increasing Ti content can prevent segregation issues and reduce the elastic modulus.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Biomedical
Liliana Verestiuc, Mihaela-Claudia Spataru, Madalina Simona Baltatu, Maria Butnaru, Carmen Solcan, Andrei Victor Sandu, Ionelia Voiculescu, Victor Geanta, Petrica Vizureanu
Summary: By adding silicon, the mechanical properties of the titanium alloys were significantly improved, making the TiMoSi alloys promising materials for orthopedic devices.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Hiroki Ubukata, Fumitaka Takeiri, Kazuki Shitara, Cedric Tassel, Takashi Saito, Takashi Kamiyama, Thibault Broux, Akihide Kuwabara, Genki Kobayashi, Hiroshi Kageyama
Summary: The introduction of chemical disorder by substitutional chemistry into ionic conductors is a common strategy to stabilize high-symmetric phases while maintaining ionic conductivity at lower temperatures. Hydride materials, especially Ba2-delta H3-2 delta X, show promising ionic conductivity below 300 degrees C, opening new directions in electrochemical use of hydrogen. The layered anion order in these materials, along with Schottky defects, helps suppress structural transitions and retain a highly symmetric lattice.
Article
Materials Science, Ceramics
Zanlin Cheng, Wenyu Lu, Lei Chen, Meng Li, Xuxu Han, Mei Li, Yujin Wang, Chengyu Zhang
Summary: The compressive creep properties of (Ti-Zr-Nb-Ta-Mo)C high-entropy ceramics were studied and found to exhibit higher creep resistance and steady-state creep rates compared to TaC. The creep mechanisms of the HEC involve dislocation motion, grain boundary sliding, and atom diffusion. Additionally, the atom diffusion is less active in (Ti-Zr-Nb-Ta-Mo)C due to sluggish lattice diffusion.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
M. Paghandeh, A. Zarei-Hanzaki, H. R. Abedi, Y. Vahidshad, J. Kawalko, D. Dietrich, T. Lampke
Summary: This study investigated the warm temperature deformation behavior of the Ti-6Al-4V alloy through tension and compression tests. It was found that the material exhibited low compressive formability and premature fracture at lower temperatures, while showing increased work hardening capacity in tensile mode. The higher activity of pyramidal slip systems in tensile mode contributed to substructure development and higher strain accommodation.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Engineering, Chemical
Alena S. Gornakova, Anna Korneva, Alexander I. Tyurin, Natalia S. Afonikova, Askar R. Kilmametov, Boris B. Straumal
Summary: The paper investigates the impact of HPT on phase transformations and mechanical properties in Ti alloys with different Mo contents. The results show that HPT can significantly increase the hardness and nanohardness of the samples, and the values of hardness and Young's modulus depend on the applied load.
Review
Chemistry, Physical
Mi Zhao, Wei Ye, Mengyuan Zhu, Yuteng Gui, Wei Guo, Shusen Wu, Youwei Yan
Summary: Mo-Si-B alloys have been extensively studied due to their high melting points, excellent high-temperature strength, and relatively good oxidation resistance. However, their insufficient room-temperature fracture toughness and high-temperature oxidation resistance hinder further application. By macroalloying Ti, a novel phase equilibrium can be established, resulting in improved mechanical properties and oxidation resistance. Understanding the advantages of quaternary alloys over ternary systems may lead to the development of novel ultra-high-temperature structural materials.
Article
Chemistry, Physical
Chen Shen, Klaus-Dieter Liss, Mark Reid, Zengxi Pan, Xueming Hua, Fang Li, Gang Mou, Ye Huang, Bosheng Dong, Dongzhi Luo, Huijun Li
Summary: In this paper, Fe3Ni-FeNi compositionally graded material (FGM) was fabricated using an innovative wire-arc additive manufacturing process to achieve high thermal lattice structural stability and high corrosion resistance. A subsequent homogenization post-production heat treatment was applied to stabilize the phase composition and eliminate possible segregation in the sample. The high intensity neutron diffraction instrument WOMBAT was used to measure the phase evolution processes in-situ, showing that the FGM has uniform Ni content gradient but hot cracking defects due to inadequate interpass temperature setting.
Article
Materials Science, Multidisciplinary
Asaf Dana, Hiroshi Sekiguchi, Koki Aoyama, Eilon Faran, Klaus-Dieter Liss, Doron Shilo
Summary: The study reveals that the reverse martensitic transformation undergoes three stages on the microsecond scale, initially occurring in a thin layer near the surface before progressing to the bulk of the wire. By fitting theoretical models to experimental results, insight is gained into the kinetic relation between the velocity of the phase front and the driving force, supporting a scenario in which a high-specific energy front propagates inward along the wire radius.
SHAPE MEMORY AND SUPERELASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Megumi Kawasaki, Jae-Kyung Han, Xiaojing Liu, Yusuke Onuki, Yulia O. Kuzminova, Stanislav A. Evlashin, Alexander M. Pesin, Alexander P. Zhilyaev, Klaus-Dieter Liss
Summary: Lab-scale X-ray diffraction and in situ heating neutron diffraction were conducted to evaluate structural changes in an additive-manufactured (AM) 316L stainless steel. The study found sequential structural relaxation and linear thermal lattice expansion in the nanostructured AM steel during heating, and observed different relaxation behaviors based on changes in crystallite sizes and dislocation densities. Furthermore, the manuscript connects critical subjects in materials science of advanced manufacturing, metal processing, and properties with novel time-resolved characterization techniques.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Klaus-Dieter Liss, Xiaojing Liu, Xi Li, Jae-Kyung Han, Rian J. Dippenaar, Megumi Kawasaki
Summary: Neutron diffraction experiments on the as-received and high-pressure torsion processed Ti-45Al-7.5Nb alloys reveal microstructural, order parameter, phase, and crystallographic evolution during ramping temperature. The disorder induced by severe plastic processing can recover in the temperature range of 660-1000 K.
Article
Materials Science, Multidisciplinary
Jae-Kyung Han, Xiaojing Liu, Isshu Lee, Yulia O. Kuzminova, Stanislav A. Evlashin, Klaus-Dieter Liss, Megumi Kawasaki
Summary: In this study, structural evolution of additive manufactured 316L stainless steel through post-printing nanostructuring using high-pressure torsion at room temperature was investigated. The formation of a martensite phase and significant strain gradients were observed in the nanostructured austenitic steel. Early stage structural changes were attributed to lattice distortion by excess of dislocations and defects.
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
Jae-Kyung Han, Kunihisa Sugimoto, Megumi Kawasaki, Klaus-Dieter Liss
Summary: This study emphasizes the capability of high-energy synchrotron X-rays in investigating polymorphous phase transformations during nanostructuring and diffusion bonding of Al and Mg using high-pressure torsion. The measurements provide diffraction peak profiles at various local positions, allowing for the mapping of gradual yet significant structural changes in the Al-Mg nanocrystalline alloy, such as grain refinement and compositional broadening.
Article
Instruments & Instrumentation
Erwin Krohmer, Felix Schmeiser, Benjamin Wahlmann, Jan Rosigkeit, Gloria Graf, Petra Spoerk-Erdely, Helmut Clemens, Peter Staron, Carolin Koerner, Walter Reimers, Eckart Uhlmann
Summary: The high flux and high energy of synchrotron radiation at modern synchrotron facilities provide vast possibilities for fundamental research on metal processing technologies. In the case of laser powder bed fusion (LPBF), in situ methods are necessary to understand the dynamic thermal, mechanical, and metallurgical processes involved. This study presents three use cases at PETRA III, demonstrating the opportunities for research on LPBF technology using in situ x-ray diffraction.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Nanoscience & Nanotechnology
Shuai Xu, Mark Reid, Junpin Lin, Yongfeng Liang, Liang Yang, Jinhu Zhang, Klaus-Dieter Liss
Summary: In this study, the crystal structure, atom positions, and phase transformations of O-Ti2NbAl alloys were clarified using in-situ neutron diffraction and high-temperature X-ray diffraction methods. The research revealed a specific C m c m structure for the O phase, as well as the phase transformation sequences of Ti-24.8Al-24.3Nb alloy. Additionally, it was proven that the distinction between the omicron subvariants 01 and 02 is crystallographic nonsense.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Xiaojing Liu, Jae-Kyung Han, Yusuke Onuki, Yulia O. Kuzminova, Stanislav A. Evlashin, Megumi Kawasaki, Klaus-Dieter Liss
Summary: In this study, in situ temperature-dependent neutron experiments were conducted to investigate the microstructural evolution of additively and conventionally manufactured CoCrFeNi high-entropy alloys. The results showed that the evolution of texture after grain refinement and during heating follows the pattern observed in typical fcc metals. Both conventional and modified Williamson-Hall analyses revealed that the major contributions to microstresses are from dislocations. Furthermore, the stored energies of various factors were elaborated, and the fully recrystallized nanostructured material exhibited the lowest dislocation density.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Physics, Applied
Amitesh Paul, Xiaojing Liu, Megumi Kawasaki, Klaus-Dieter Liss
Summary: We observe unconventional magnetization behaviors in a high-pressure torsion processed CoCrFeNi high-entropy alloy. The magnetization protocol and DC susceptibility reveal the effects of spin-clustering, indicating a change in magnetic properties from superparamagnetic to superspin glass dynamics. The material shows an inverted magnetic hysteresis loop, with the remanent magnetization pointing in the opposite direction to the applied field. This spin-clustering phenomenon is attributed to a non-equilibrium population of oppositely polarized domains in an ordered ferromagnetic state enabled by the nanostructured, highly distorted, and locally disordered crystalline medium.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xiaojing Liu, Pingguang Xu, Ayumi Shiro, Shuoyuan Zhang, Takahisa Shobu, Eitaro Yukutake, Koichi Akita, Emil Zolotoyabko, Klaus-Dieter Liss
Summary: This study utilized in situ time/temperature-resolved synchrotron high-energy X-ray diffraction to investigate the heat-mediated structural changes and phase transformations in rolled sheets of AZ91 and AZ31 magnesium alloys. The study found significant differences in the stability and dissolution of intermetallic precipitates in the two different alloys.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Asaf Dana, Emil Bronstein, Eilon Faran, Veijo Honkimaki, Klaus-Dieter Liss, Doron Shilo
Summary: The martensitic transformation in shape memory alloys is known to be very fast. However, its rate in bulk materials that serve in common actuator applications is still an open question. In this study, the researchers induced the martensitic transformation in a polycrystalline NiTi shape memory alloy wire using a high-voltage microsecond superheating pulse, and tracked its rate using time-resolved X-ray diffraction. They found that the transformation rate follows the rate of heating, completing most of the process within approximately 1 µs, but a part of the transformation continues at much slower time scales of several tens of microseconds.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Isshu Lee, Laxman Bhatta, Yun-Hsuan Wu, Lukas Daut, Roberto B. Figueiredo, Klaus-Dieter Liss, Brian K. Bay, Melissa K. Santala, Megumi Kawasaki
Summary: The cold angular rolling process (CARP) is a continuous severe plastic deformation technique for metal sheets. It can process sheets without any length limitations at room temperature and achieve desired microstructure and mechanical properties. In this study, copper sheets with different widths were processed using CARP to evaluate its capability. Lab-scale X-ray diffraction and tensile testing were conducted to analyze the evolution in dislocation density and mechanical properties of the CARP-treated sheets. The results confirm the potential of CARP as a useful sheet process for strengthening ductile metals.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Klaus-Dieter Liss, Pingguang G. Xu, Ayumi Shiro, Shuoyuan Y. Zhang, Eitaro Yukutake, Takahisa Shobu, Koichi Akita
Summary: White-beam Laue synchrotron X-ray diffraction is used to study the erratic behavior of grain reorientation in fine-grained, as-rolled magnesium alloy during an in situ heating experiment. The observation of grain rotations and coalescence provides crucial insights into anomalous grain growth, a phenomenon that has long been postulated but lacked observational methods. The findings have implications for a wide range of materials undergoing grain growth, creep, and superplasticity.
ADVANCED ENGINEERING MATERIALS
(2023)
