Article
Materials Science, Multidisciplinary
Michael Wurmshuber, Markus Alfreider, Stefan Wurster, Michael Burtscher, Reinhard Pippan, Daniel Kiener
Summary: The brittleness of tungsten is a challenge for its application as a divertor material in nuclear fusion reactors. Grain refinement is a promising strategy to increase its fracture toughness, but it also promotes intercrystalline crack growth. This study explores the use of grain boundary doping with boron and hafnium to enhance the fracture toughness of ultrafine-grained tungsten. The results show that doping with boron and hafnium can improve the fracture toughness of ultrafine-grained tungsten, with values up to 27 MPa root m.
Article
Physics, Fluids & Plasmas
J. S. Langer
Summary: This paper attempts to construct a first-principles theory of the fracture toughness of crystalline solids based on the thermodynamic dislocation theory. The analysis results show that the theory's predictions quantitatively agree with experimental data, including both brittle and ductile fracture under various conditions.
Article
Engineering, Geological
Zongze Li, Yanfei Kang, Jinyang Fan, Marion Fourmeau, Deyi Jiang, Daniel Nelias
Summary: Salt rock, a widely distributed sedimentary rock in the crust, has been extensively used for subsurface energy storage and waste disposal due to its low permeability, rheological behavior, and self-healing characteristics. The stability of the salt cavern surrounding rock is critical to the function of a compressed air energy storage (CAES) plant.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Multidisciplinary
Richard M. Christensen
Summary: The transition from ductile to brittle behavior is determined to occur at specific values of certain material properties, with a strong relationship found with the elements of the Periodic Table, particularly iron. These findings extend beyond elemental materials and have significant implications for understanding the elastic and failure properties of materials. These developments build upon previous empirical observations from Pugh [7] and provide a broader insight into material behavior.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Yan Lu, Wei-Zhong Han
Summary: The low temperature toughness of BCC metals, such as chromium, can be greatly enhanced by designing a fine-grained structure. The fine grains act as dislocation sources, emitting easy glide edge dislocations at low temperature, which effectively slows down crack propagation and increases the toughness of chromium.
SCRIPTA MATERIALIA
(2024)
Article
Chemistry, Physical
Yinhui Wang, Zhiqiang Liang, Wenxiang Zhao, Xibin Wang, Hao Wang
Summary: This work investigates the anisotropic cutting mechanisms on the surface quality of sapphire in ultra-precision machining. The results show that the ductile-to-brittle transition (DBT) depth is influenced by the machining direction. The evaluation of DBT depths, subsurface damage, and cutting forces is essential for optimizing the precision machining of sapphire.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Chenghao Chen, Min Lai, Fengzhou Fang
Summary: This paper investigates the crack formation mechanism in nano-cutting of gallium arsenide, finding that the main damage changes from dislocation to phase transformation with increasing cutting speed. The amount of cracks increases with higher cutting depth, and the deformation mode turns from ductile to a combination of ductile and brittle.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
L. Oger, S. Vernier, J. -m. Cloue, P. Joly, L. Laffont, E. Andrieu
Summary: The study focuses on the segregated microstructures of Mn-Mo-Ni bainitic alloys and investigates the evolutions of local mechanical properties with temperature. The analysis reveals that the significant increase in hardness and the extension of brittle surfaces are critical parameters for the brittle fracture.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Ceramics
Chong Su, Hujiao Tang, Pinfang Guo, Ruiming Ren
Summary: In this study, mechanisms of ductile-brittle transition and crack damage during the grinding of plasma-sprayed alumina ceramic coatings were investigated. The results showed that brittle damage modes include boundary cracks, median cracks, and lateral fractures. The normal force of the abrasive grain initiates median cracks, while the tangential force propagates them. The geometry and cutting depth of the abrasive grain significantly influence the transition, while the cutting speed has no significant influence. Stress concentration at pore defects leads to crack propagation to the deep layer and reduces the local strength, resulting in brittle fracturing and interrupted crack propagation. Exposed pores and their broken morphology are important factors in reducing surface roughness. The machined surface morphology includes brittle fracturing, ductile cutting and plowing, cracks, original pores, and unmelted particles.
CERAMICS INTERNATIONAL
(2023)
Article
Polymer Science
Qi Yan, Tingyu Xu, Wenwen Zhang, Changzhu Lv, Hang Guo, Fucheng Tian, Wei Chen, Liangbin Li
Summary: This study investigates the effect of molecular alignment on the mechanical response of glassy polymers by comparing two different pre-stretching methods of poly(methyl methacrylate) (PMMA). It was found that the width-Constrained Melt pre-Stretched (CMS) samples exhibited higher ductility in both the stretching direction and transverse direction due to more chain stretching and aligned chain density. Conversely, the width-Free Melt pre-Stretched (FMS) samples tended to experience more crazing during further deformation, resulting in weaker ductility.
Article
Engineering, Mechanical
Shi Hu, Jianwei Li, Quanyi Liu, Yuanhua He
Summary: In this study, the nanoscale crack propagation behavior in the presence of nonlinear disturbance strains was investigated using the phase-field-crystal method. The influences of amplitude A and frequency omega on fracture mode and crack growth were discussed, showing that the disturbance strains could induce transitions between brittle and ductile fracture modes. The results also revealed that increasing frequency omega can lead to a brittle-to-ductile transition (BDT), while further increasing omega can cause a ductile-to-brittle transition (DBT), with the amplitude A affecting the critical frequencies for these transitions. Additionally, crack growth was found to be influenced by the disturbance strains, with smaller omega accelerating crack growth and larger omega requiring an increase in A to retard it. Through this work, a new approach for effectively exploring the nanoscale mechanism and behavior of crack propagation was provided.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2021)
Review
Mechanics
Richard M. Christensen
Summary: The formalism of isotropic elasticity theory can benefit from a review and re-examination of its structure, leading to a realignment of the basic moduli type properties. Understanding ductile versus brittle failure behaviors becomes more accessible with this approach. The ductile/brittle transition in uni-axial tension can be specified in terms of the two elastic moduli 2 mu and k. The implications of these findings are discussed in the context of general failure theory.
APPLIED MECHANICS REVIEWS
(2023)
Article
Geochemistry & Geophysics
Melodie E. French, Wenlu Zhu, Xiaohui Xiao, Brian Evans, David J. Prior
Summary: This study reports the strength and deformation behavior of Solnhofen limestone during its transition from brittle to ductile. The results show that the combined effects of water and temperature have complex influences on the deformation and strength of the limestone. At elevated temperatures, water-saturated limestone exhibits weakening in both the brittle and ductile fields. Moreover, the concurrent effects of pore water and temperature significantly reduce the pressure of the brittle to ductile transition. These findings are important for understanding the behavior of limestone in geological processes.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Materials Science, Multidisciplinary
Alena Uhnakova, Anna Machova, Jan Cerv, Petr Hora, Jaroslav Joch
Summary: Through molecular dynamics simulations, it was found that cleavage fracture is supported by surface emission of oblique dislocations and their subsequent cross slip, which increases separation of the cleavage planes inside the crystal. Under slower loading rates, crack growth is hindered by the generation of twins on oblique planes, resulting in a ductile fracture.
MATERIALS RESEARCH EXPRESS
(2022)
Article
Geosciences, Multidisciplinary
J. R. Peacock, D. L. Siler
Summary: The Great Basin in the western United States is home to a variety of hydrothermal systems, including both active geothermal systems and ancient systems preserved as mineral deposits. Research in the Gabbs Valley area of western Nevada shows that hydrothermal systems are controlled by both bottom-up factors such as weaknesses in the crust, and top-down factors such as modern tectonics. Imaging lower crustal structures and preferential pathways to the surface can better inform the characterization of regional mineral and geothermal resources.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
B. Schuh, F. Mendez-Martin, B. Voelker, E. P. George, H. Clemens, R. Pippan, A. Hohenwarter
Article
Physics, Multidisciplinary
T. Vojtek, J. Pokluda, A. Hohenwarter, R. Pippan
ACTA PHYSICA POLONICA A
(2015)
Article
Engineering, Mechanical
T. Vojtek, J. Pokluda, P. Sandera, J. Hornikova, A. Hohenwarter, R. Pippan
INTERNATIONAL JOURNAL OF FATIGUE
(2015)
Article
Nanoscience & Nanotechnology
Thomas Leitner, Anton Hohenwarter, Reinhard Pippan
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2015)
Article
Materials Science, Multidisciplinary
M. W. Kapp, A. Hohenwarter, S. Wurster, B. Yang, R. Pippan
Article
Engineering, Mechanical
Tomas Vojtek, Jaroslav Pokluda, Anton Hohenwarter, Reinhard Pippan
INTERNATIONAL JOURNAL OF FATIGUE
(2016)
Article
Engineering, Mechanical
Tomas Vojtek, Anton Hohenwarter, Reinhard Pippan, Jaroslav Pokluda
INTERNATIONAL JOURNAL OF FATIGUE
(2016)
Article
Multidisciplinary Sciences
Bernd Gludovatz, Anton Hohenwarter, Keli V. S. Thurston, Hongbin Bei, Zhenggang Wu, Easo P. George, Robert O. Ritchie
NATURE COMMUNICATIONS
(2016)
Article
Materials Science, Multidisciplinary
Ivana Dimic, Ivana Cvijovic-Alagic, Bernhard Voelker, Anton Hohenwarter, Reinhard Pippan, Dorde Veljovic, Marko Rakin, Branko Bugarski
MATERIALS & DESIGN
(2016)
Article
Materials Science, Multidisciplinary
Claudio L. P. Silva, Marcelo A. Camara, Anton Hohenwarter, Roberto B. Figueiredo
Summary: Severe plastic deformation has been shown to significantly improve the mechanical strength, ductility, and corrosion resistance of pure magnesium, particularly for biodegradable applications. Processing methods such as ECAP and HPT can reduce anisotropy, increase strength, and enhance strain rate sensitivity in the material. Furthermore, severe plastic deformation has been found to induce uniform corrosion and reduce the overall corrosion rate compared to as-cast material.
Article
Chemistry, Multidisciplinary
Stefan Wurster, Martin Stueckler, Lukas Weissitsch, Heinz Krenn, Anton Hohenwarter, Reinhard Pippan, Andrea Bachmaier
Summary: The paper discusses the capability of magnetic softening of a coarse-grained bulk material using a severe deformation technique and its relation to microstructure and magnetic properties. The study finds that the coercive field decreases dramatically for grains smaller than the magnetic exchange length. By starting with a two-phase microstructure, the material can be substantially refined, allowing for the investigation of magnetic properties in nanocrystalline bulk materials.
Article
Materials Science, Multidisciplinary
Christian Gruber, Peter Raninger, Juergen Maierhofer, Hans-Peter Gaenser, Aleksandar Stanojevic, Anton Hohenwarter, Reinhard Pippan
Summary: This study investigates the effect of microstructures of Alloy 718 on the threshold of stress intensity factor range, and draws conclusions through a series of experiments. Different processing steps are tailored to achieve specific mechanical and microstructural properties in the final product.
Article
Chemistry, Multidisciplinary
Benjamin Schuh, Inas Issa, Timo Mueller, Thomas Kremmer, Christoph Gammer, Reinhard Pippan, Anton Hohenwarter
Summary: A nanocrystalline CrMnFeCoNi high-entropy alloy underwent phase decomposition and formed a multi-phase structure after annealing at selected temperatures and times (450 degrees C for 1 h and 15 h and at 600 degrees C for 1 h) following severe plastic deformation by high-pressure torsion. The possibility of tailoring a favorable composite architecture by redistributing, fragmenting, or partially dissolving the additional intermetallic phases was investigated by subjecting the samples to high-pressure torsion again. While the second phase in the 450 degrees C annealing states exhibited high stability against mechanical mixing, partial dissolution could be achieved in the samples subjected to 600 degrees C for 1 h.
Article
Materials Science, Multidisciplinary
J. Pokluda, T. Vojtek, A. Hohenwarter, R. Pippan
FRATTURA ED INTEGRITA STRUTTURALE
(2015)
Proceedings Paper
Materials Science, Multidisciplinary
O. Renk, A. Hohenwarter, B. Schuh, J. H. Li, R. Pippan
36TH RISO INTERNATIONAL SYMPOSIUM ON MATERIALS SCIENCE
(2015)