Article
Nanoscience & Nanotechnology
N. Li, L. H. Wu, Z. K. Li, H. M. Fu, Z. W. Zhu, P. Xue, F. C. Liu, D. R. Ni, B. L. Xiao, Z. Y. Ma
Summary: The superplastic behavior of CoCrFeNiCu HEA fabricated by friction stir processing (FSP) was investigated for the first time in this study at the temperature range of 900-950°C and strain rate range of 3 x 10-4-3 x 10-2 s-1. The FSP CoCrFeNiCu HEA exhibited excellent superplasticity with a maximum elongation of 620% and low flow stress of 5 MPa. The ultrafine grained structure and high angle grain boundaries contributed to its superior performance.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Geochemistry & Geophysics
Xiaofeng Chen, Sai Sandeep Chitta, Ximeng Zu, Ze'ev Reches
Summary: This study investigates the weakening processes of faults during earthquakes, emphasizing that the weakening at the rupture-front is more efficient than frictional weakening. Experimental results show that the rupture-front can rapidly weaken the entire fault, possibly occurring in natural faults as well.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Dianguang Liu, Kewei Wang, Ke Zhao, Jinling Liu, Linan An
Summary: This study systematically investigated the tensile creep of 3 mol% Y2O3 stabilized tetragonal ZrO2 ceramics under a DC field. The results showed that the deformation mechanism of the material strongly depended on the current density and applied stress. Exceptionally large uniform elongation can be obtained when the creep is dominated by dislocation accommodated grain-boundary sliding.
SCRIPTA MATERIALIA
(2022)
Article
Nanoscience & Nanotechnology
Anastasia V. Mikhaylovskaya, Olga A. Yakovtseva, Natalia Yu. Tabachkova, Terence G. Langdon
Summary: During superplastic deformation of microduplex-structured brasses, strain primarily occurs in the beta-phase through grain boundary sliding and dislocation slip/creep mechanisms. Dynamic recrystallization and twinning transform the initial coarse beta-phase grains into ultrafine grains, and alloying with Al improves superplastic behavior and reduces residual cavitation.
SCRIPTA MATERIALIA
(2022)
Article
Geochemistry & Geophysics
J. Ding, F. M. Chester, J. S. Chester, X. Shen, C. Arson
Summary: The operation of fracture, diffusion, and intracrystalline-plastic micromechanisms during semibrittle deformation of rock is directly relevant to understanding mechanical behavior across the brittle-plastic transition in the crust. Experimental results with synthetic salt-rocks suggest coupled operation of micromechanisms leading to a distinct rheology, indicating the need to consider interactions between multiple microscopic processes to accurately describe the mechanical behavior of rocks. The study highlights the importance of water content and deformation rates in influencing mechanical behavior, with chemical reactions along grain boundaries playing a significant role in deformation processes.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Metallurgy & Metallurgical Engineering
Oscar A. Ruano, Marta Alvarez-Leal, Alberto Orozco-Caballero, Fernando Carreno
Summary: Through friction stir processing, the WE54 magnesium alloy obtained superplasticity at high temperatures, with grain sizes less than 1μm and a tensile superplastic elongation of 756%, attributed to the grain boundary sliding mechanism (GBS).
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Review
Materials Science, Multidisciplinary
Roberto B. Figueiredo, Megumi Kawasaki, Terence G. Langdon
Summary: The grain size and grain boundary density have significant effects on the flow stress of metallic materials. The Hall-Petch grain refinement strengthening effect, which is a linear relationship to the inverse of the square root of the grain size, has been well-established for more than 70 years. However, grain refinement softening can occur at high homologous temperatures and both effects have been treated separately. Recent research has shown that a general relationship can explain both the Hall-Petch strengthening effect at low temperatures and superplasticity at high temperatures. This review discusses recent advances in structural and mechanical characterization and provides an updated analysis of the relationship between grain size and flow stress.
PROGRESS IN MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Qing Zhang, Xiaofei Ju, Jun Liu, Lei Wang, Yang Li, Haowei Wang, Zhe Chen
Summary: The addition of TiB2 nanoparticles as reinforcement in Al-Zn-Mg-Cu composite leads to the formation of fine-equiaxed grains, which enhances both the elongation and thermal stability of the material. The deformation at grain boundaries is controlled by grain boundary sliding mechanism, and the stress release and prevention of cavitation are facilitated by locally melted Mg-rich phases.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Chuangchuang Duan, Yujie Wei
Summary: This paper investigates the relaxation mechanisms in polycrystalline materials, highlighting the impact of grain boundary diffusion and viscous flow on material properties. The research shows that different competitive deformation mechanisms can affect the dependence of relaxation time on grain size.
SCIENCE CHINA-MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Zeinab Savaedi, Hamed Mirzadeh, Rouhollah Mehdinavaz Aghdam, Reza Mahmudi
Summary: Shear punch testing was used to evaluate the superplasticity of a hot rolled fine-grained Mg-3Zn-0.5RE-0.5Zr (ZEK300) alloy. The alloy exhibited regions I, II, and III of deformation behavior typical of superplastic materials, with a grain size of 4.5 μm. In region II, the strain rate sensitivity indices of the ZEK300 alloy were determined to be 0.51, 0.48, and 0.41 at temperatures of 350, 400, and 450 degrees C, respectively. The average activation energy of 87.6 kJ mol-1 suggests that grain boundary sliding (GBS) facilitated by grain boundary diffusion is the dominant deformation mechanism.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Hyun-Bin Jeong, Jin-Young Lee, Ju-Chan Jin, Hyung-Jin Cho, Young-Kook Lee
Summary: In this study, a Fe-Mn-Si-Ni steel was developed to exhibit superplasticity at a low temperature and a high strain rate, while maintaining remarkable room-temperature tensile strength and total elongation. The excellent superplasticity was achieved by grain boundary sliding at the boundaries of fine gamma grains, which were prevented from coarsening by Fe5(Mn,Ni)3Si2 and (Fe,Mn,Ni)3Si precipitates.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Geosciences, Multidisciplinary
Giacomo Pozzi, Nicola De Paola, Stefan B. Nielsen, Robert E. Holdsworthl, Telemaco Tesei, Manuel Thieme, Sylvie Demouchy
Summary: Laboratory experiments show that fault materials weaken dramatically when sheared at seismic velocities, but existing mechanisms cannot fully explain this weakening. Research indicates that viscous deformation, at sub- or super-solidus temperatures, is a prevalent lubrication process during earthquakes, providing more energy for rupture propagation and hazardous seismic wave radiation.
Article
Materials Science, Multidisciplinary
Jianheng Cai, Hua Wang, Cheng Qiu, Genghua Cao, Datong Zhang
Summary: ZK60 magnesium alloy is refined through submerged friction stir processing (SFSP), leading to the observation of high-strain-rate superplasticity (HSRS) at elevated temperature. The excellent HSRS is attributed to the uniform fine-grained structure and the relatively high fraction of high-angle grain boundaries, which facilitate grain boundary sliding. Additionally, the presence of dispersed fine particles/precipitates enhances the microstructural stability of the specimens.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Seok-Hyeon Kang, Hyun-Bin Jeong, Jin-Sung Hong, Young-Kook Lee
Summary: The influence of B on the superplasticity of Fe-6.6Mn-2.0Al alloy was studied using high-temperature tensile testing. The addition of B increased peak stress and apparent activation energy, while decreasing strain rate sensitivity, affecting grain size and phase fraction. The increase in elongation with B addition may be attributed to the finer grains achieved by suppressing dynamic grain growth.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Geosciences, Multidisciplinary
Mathias Lebihain, Thibault Roch, Marie Violay, Jean-Francois Molinari
Summary: The study presents a comprehensive analytical framework to predict the influence of linearly slip-dependent friction laws on earthquake nucleation length. Results show that the interplay between frictional properties and asperity size leads to three instability regimes, and that the influence of heterogeneities at a scale far lower than the nucleation length can be averaged.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
L. R. Campbell, G. E. Lloyd, R. J. Phillips, R. C. Walcott, R. E. Holdsworth
Summary: Heterogeneous sequences of exhumed fault rocks along the Outer Hebrides Fault Zone in NW Scotland preserve a record of the long-term evolution of fault strength and deformation behavior. The seismicity in the fault zone is complex, with a range of fault orientations, slip directions, and slip senses, indicating a long-term presence of seismic activity across the fault zone.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2021)
Article
Geosciences, Multidisciplinary
Timothy B. Armitage, Lee M. Watts, Robert E. Holdsworth, Robin A. Strachan
Summary: The study highlights the structural evolution of the Walls Boundary Fault in Shetland, which experienced complex tectonic events resulting in right-lateral transpressional deformation. The structures and strain distribution on both sides of the Walls Boundary Fault show significant geological differences, reflecting the episodic nature of tectonic movements.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2021)
Article
Geosciences, Multidisciplinary
A. M. Dichiarante, R. E. Holdsworth, E. D. Dempsey, K. J. W. McCaffrey, T. A. G. Utley
Summary: A recent structural study in Scotland revealed three phases of deformation in the Devonian Orcadian Basin, including Devonian extensional faults, late Carboniferous-early Permian inversion, and Permian reactivation. The complex structural features onshore reflect both the reactivation of pre-existing faults and the superimposition of obliquely oriented rifting episodes during basin development in offshore areas.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2021)
Article
Geosciences, Multidisciplinary
E. D. Dempsey, R. E. Holdsworth, D. Selby, A. Bird, B. Young, C. Le Cornu
Summary: Mineralization and fluid migration events in the North Pennine Orefield are associated with tectonic activity and magma emplacement, with previous models no longer applicable. The new findings suggest a reevaluation of equivalent base metal sulfide fields worldwide.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2021)
Article
Geochemistry & Geophysics
R. Ruggieri, M. M. Scuderi, F. Trippetta, E. Tinti, M. Brignoli, S. Mantica, S. Petroselli, L. Osculati, G. Volonte, C. Collettini
Summary: The presence of weak phyllosilicates in mature carbonate fault zones can significantly affect frictional strength, stability, and healing, especially under wet conditions. An increase in shale content leads to a reduction in frictional strength and a transition from velocity-weakening to velocity-strengthening behavior.
Article
Geosciences, Multidisciplinary
Alexandra Tamas, Robert E. Holdsworth, John R. Underhill, Dan M. Tamas, Edward D. Dempsey, Dave J. McCarthy, Ken J. W. McCaffrey, David Selby
Summary: This paper demonstrates how targeted interpretation of offshore seismic reflection data can enhance an onshore study, allowing for the separation and characterisation of different deformation events in superimposed basins. By correlating onshore and offshore data, the authors were able to determine the ages and evidence of fault reactivation in the studied area. This workflow can be applied to other rift basins with continuous onshore-offshore expressions, providing valuable insights into their deformation history.
Article
Geochemistry & Geophysics
G. Volpe, G. Pozzi, E. Carminati, M. R. Barchi, M. M. Scuderi, E. Tinti, L. Aldega, C. Marone, C. Collettini
Summary: Crustal seismicity usually occurs within the seismogenic layer, which is typically below 10 km depth, and its lower boundary is influenced by the properties of the sedimentary cover and rock. Studies in the central-northern Apennines have shown that seismic sequences primarily occur within the sedimentary cover, indicating the significant role of the basement in dictating the depth of the seismogenic zone.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Giacomo Pozzi, Marco M. Scuderi, Elisa Tinti, Manuela Nazzari, Cristiano Collettini
Summary: Fault stability is closely related to the frictional and healing properties of fault rocks and associated fabrics. The reactivation and slip behavior of dolomite-anhydrite analog faults are controlled by fault fabrics. The study reveals that changes in normal stress can result in different fault behaviors, such as large stress drops and high slip velocities, or low stress drops and slow stick-slip events. The integration of microstructural and mechanical data suggests that frictional and chemically assisted healing processes play a relevant role in developing large instabilities in natural faults. Additionally, fault rock heterogeneity modulates the slip velocity function and the dynamics of repeating stick-slip cycles.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Multidisciplinary Sciences
C. Collettini, M. R. Barchi, N. De Paola, F. Trippetta, E. Tinti
Summary: Analysis of the 2016-2017 Central Italy seismic sequence reveals that seismic activity not only occurs along major fault structures, but also within volumes of Triassic Evaporites with a different frequency-magnitude distribution. The study suggests that ductile crustal deformation can cause distributed microseismicity.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
K. Hardman, R. E. Holdsworth, G. Palladino, G. Prosser, Z. Killingback, K. J. W. McCaffrey
Summary: Basement-hosted fissure-fill networks in sub-unconformity settings are important for reservoirs and migration pathways. The well-exposed fissures in southern Italy provide insights into their nature, origin and evolution. The fissure network hosts marine sediments, collapse breccias and limited mineralization. These highly connected fissure networks were formed due to rifting and extend to depths of at least 150 m below the erosion surface.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Geosciences, Multidisciplinary
Lee M. Watts, Robert E. Holdsworth, David Roberts, Janine M. Sleight, Richard J. Walker
Summary: The ENE-WSW-trending More-Trondelag Fault Complex (MTFC) in Central Norway is a 10-50 km-wide, steeply dipping reactivated fault zone that played a major role in controlling the architecture of the More Basin and the Viking Graben. The complex comprises two major fault strands: the Hitra-Snasa Fault (HSF) and the Verran Fault (VF), which have a prolonged and heterogeneous kinematic history.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Geosciences, Multidisciplinary
K. Hardman, R. E. Holdsworth, L. Scott, E. Dempsey, K. J. W. McCaffrey
Summary: Exhumed examples of ancient fault voids formed during seismic slip at depths >10 km are well preserved in the Assynt Terrane of the Lewisian Complex, NW Scotland. They are interpreted to have formed during regional Mesoproterozoic (c. 1.55 Ga; 'Assyntian') strike-slip faulting. Reactivation occurred at palaeodepths of 10-15 km, where frictional-viscous deformation synchronous with co-seismic frictional melting led to cycles of millimetre- to decimetre-scale cavity dilation and collapse.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Geosciences, Multidisciplinary
Qingqing Sun, Tailiang Fan, Robert E. Holdsworth, Zhiqian Gao, Jun Wu, Shichang Gao, Ming Wang, Yaxuan Yuan
Summary: The seismic reflection data from the Tarim Basin reveals the characteristics of deeply buried strike-slip faults and their impact on reservoir distributions. Restraining and releasing stepovers produce different structures and deformation zones, with restraining stepovers exhibiting wider zones and higher fracture density. The fractures in the reservoirs of restraining stepovers comprise stylolite meshes and mosaic breccias, while the narrower releasing stepovers are prone to developing cavities and dilational breccias. Both types of stepovers are asymmetric, except in fault overlap zones. Lithological layering and tectonic processes also contribute to the three-dimensional complexity of the reservoirs.
JOURNAL OF STRUCTURAL GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
T. A. G. Utley, R. E. Holdsworth, G. A. Blackbourn, E. Dempsey, R. A. Strachan, K. J. W. McCaffrey, A. C. Morton, A. F. Bird, R. R. Jones, A. Sassnowski, R. J. Walker
Summary: The island of Foula preserves a thick sequence of Middle Devonian sandstones, which are exposed in high cliff sections. These rocks overlie Precambrian basement rocks and were deposited contemporaneously with growth folding and faulting. The large-scale structural geometry suggests a regional strain associated with transtensional movements during the Mid-Devonian. This study also suggests that transtensional fold development may be more widespread in Devonian basins than previously realized.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Geochemistry & Geophysics
Corentin Noel, Carolina Giorgetti, Marco M. Scuderi, Cristiano Collettini, Chris Marone
Summary: Fault stability is influenced by fault zone width, structural complexity, fault rock wear rate, and the presence of gouge during frictional sliding. Shear displacement plays a key role in the transition from stable to unstable sliding, and strain localization is an important factor controlling fault stability. The rate-and-state parameters (a-b) and D-c are affected by shear displacement and wear rate, with enhanced velocity weakening and potential instability observed for larger fault slip.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)