Article
Materials Science, Multidisciplinary
Ryan Schoell, Li Xi, Harvey West, Peter Hosemann, Jun-Sang Park, Peter Kenesei, Jonathan Almer, Zeev Shayer, Djamel Kaoumi
Summary: The effect of fatigue on the microstructure of three variations of 304 stainless steels was investigated using synchrotron x-ray tomography and diffraction. It was found that fatigue induced the formation of microvoids and cracks, and the chemical nature and shape of precipitates/inclusions played a role in microvoid formation.
MATERIALS CHARACTERIZATION
(2022)
Article
Mechanics
Ce Xiao, Jean-Yves Buffiere
Summary: In this study, an image segmentation method based on convolutional neural network is developed to successfully extract the 3D shapes of internal fatigue cracks in metals, combined with a 'Hessian matrix' filter.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
Ce Xiao, Jean-Yves Buffiere, Jean Michel Letang, Wolfgang Ludwig
Summary: The higher lateral coherence length of beams at high brilliance synchrotron sources can improve crack detectability in Synchrotron Radiation Computed Tomography (SRCT) images, but non-planar cracks may lead to strong artifacts, making quantitative crack analysis difficult. Investigation through phase contrast tomography simulations showed that these artifacts come from Fresnel interference patterns on the detector, which can be minimized by reducing phase contrast intensity or inclining cracks with respect to the beam trajectory plane.
MATERIALS CHARACTERIZATION
(2022)
Article
Engineering, Mechanical
David B. Menasche, Paul A. Shade, Peter Kenesei, Jun-Sang Park, William D. Musinski
Summary: In this study, we nondestructively imaged the microstructure of a low-solvus high refractory (LSHR) nickel base specimen during cyclic loading to investigate crack propagation during the microstructurally small crack (MSC) growth regime. The results showed that the crack formed at a stress concentration location and propagated along a specific crystallographic plane. Analysis also revealed slower crack growth along directions favoring zig-zag cross and codirectional cross slip.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Nanoscience & Nanotechnology
Louis Hebrard, Jean-Yves Buffiere, Thierry Palin-Luc, Nicolas Ranc, Marta Majkut, Andrew King, Arnaud Weck
Summary: In this study, physically short fatigue cracks initiated from an artificial internal notch under vacuum conditions are observed in smooth specimens made of titanium alloy. The role of environment in the explanation of the low crack growth rate of internal short crack loaded at very low stress amplitude leading to the gigacycle regime is examined. Ultrasonic cycling and synchrotron micro-computed tomography acquisitions were used to analyze the number of cycles to failure, the internal crack growth rate, and the crack growth mechanisms of internal cracks under different conditions.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Yishan Bai, Shanglei Yang, Minqi Zhu, Cong Fan
Summary: Using synchrotron radiation X-ray imaging, this study examined the microstructure, tensile properties, and fatigue properties of FGH96 nickel-based superalloy. The alloy showed a dense structure without voids or defects, with high tensile strength and fatigue strength. Fatigue fractures exhibited characteristics of cleavage and ductile fractures, with crack propagation showing Z-shaped pattern under cyclic loading and tip passivation.
Article
Engineering, Mechanical
Valary Tubei, Hiroyuki Toda, Worapol Ketanond, Hiro Fujihara, Osamu Takakuwa, Akihisa Takeuchi, Masayuki Uesugi
Summary: Local 3D short fatigue crack closure behavior in Ti-6Al-4V alloy was investigated using ultra-high-resolution X-ray microtomography (XMT). The study revealed that the inhomogeneous distribution of plasticity-induced and roughness-induced crack closure is caused by the variation in crack path morphologies. These crack path morphologies exhibit heterogeneous plastic deformation at the crack tips due to the anisotropic nature of alpha grains and varying extents of crack tilting and twisting caused by the interaction of the crack front with alpha/alpha boundary or alpha/alpha + beta interface. Surrogate-based statistical analysis showed that the Schmid factor has the strongest effect on crack growth rate.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Mechanics
Jesbeer Kallungal, Laurent Chazeau, Jean-Marc Chenal, Jerome Adrien, Eric Maire, Claire Barres, Bernard Cantaloube, Patrick Heuillet, Fabien Wilde, Julian Moosmann, Timm Weitkamp
Summary: This paper presents a precise 3D quantification of damage evolution and crack initiation in peroxide crosslinked EPDM filled with metallic oxide particles and filler agglomerates using synchrotron radiation X-ray Tomography. Polymer debonding is observed at the poles of metallic oxide particles during stretching, while crack always originates from carbon black agglomerates. The crack initiation process involves cavity nucleation, cavity growth, and eventual fracture of the agglomerates.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Chemistry, Physical
Benjamin Doenges, Melanie Syha, Anne K. Huesecken, Ullrich Pietsch, Wolfgang Ludwig, Ulrich Krupp, Hans-Jurgen Christ
Summary: Diffraction and phase contrast tomography techniques were successfully used to investigate the microstructure of a metallic material and the influence of residual stresses on fatigue crack nucleation and propagation. The study demonstrated that residual stresses accumulated in ferritic grains due to cyclic deformation promote crack formation, while microstructural barriers play a crucial role in short fatigue crack growth on the surface and within the material.
Article
Multidisciplinary Sciences
Ryan Warr, Matthew C. Jewell, Neil Mitchell, Alexander Rack, Jack Swanson, Vladimir Tronza, Robert Cernik
Summary: The study compared the performance of heat-treated and non-heat-treated CICCs using high-energy X-ray tomography, revealing that the non-heat-treated sample exhibited greater movement and bundle distortion, while the heat-treated sample showed nonlinear movements at temperatures close to 77 K.
SCIENTIFIC REPORTS
(2021)
Article
Mechanics
Yanan Hu, Ni Ao, Shengchuan Wu, Yukuang Yu, Haiou Zhang, Weijian Qian, Guangping Guo, Mingbo Zhang, Guilan Wang
Summary: HRAM technology combines micro-rolling with WAAM additive manufacturing to improve the microstructure of alloys, increasing tensile strength and ductility while also enhancing dislocation density and the size of alpha laths. This leads to optimized performance and better resistance to cracking in the processed alloy.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
J. Wang, X. Y. Jiao, H. L. Xie, B. Deng, S. M. Xiong
Summary: The fatigue crack surfaces of three high pressure die casting hypereutectic Al-Si alloy plates were characterized using synchrotron X-ray tomography and CT technology. The analyses showed that the Si content affected crack morphology and behavior, with primary silicon particles acting as obstacles for crack propagation.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Nanoscience & Nanotechnology
I Burda, K. Zweiacker, A. Arabi-Hashemi, P. Barriobero-Vila, A. Stutz, R. Koller, H. Roelofs, L. Oberli, M. Lembke, C. Affolter, C. Leinenbach
Summary: Controlling the grain size of steels has a significant impact on their mechanical properties. This study successfully achieved microstructural refinement of a low-alloyed TRIP-assisted bainitic steel through a new industrial thermomechanical treatment. Fatigue tests showed the influence of this treatment on crack propagation behavior. Electron backscatter diffraction, vibrating sample magnetometry, and high-energy synchrotron X-ray diffraction were used to analyze the microstructure near the fatigue crack tip and assess the contribution of martensitic transformation to fracture toughness.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Y. G. Tan, D. J. Bull, R. Jiang, A. Evangelou, S. Chaudhuri, S. Octaviani, F. Pierron, N. Gao, H. Toda, I Sinclair, P. A. S. Reed
Summary: The crack initiation and early propagation behavior of DS superalloy CM247LC was assessed using various imaging techniques. Three modes of secondary crack behaviors were identified, with early fatigue damage controlled by microstructure-induced cracking, mainly carbide cracking. The mechanisms of these cracking behaviors are associated with the plastic zone of the main crack tip, with carbide-induced cracking more likely to occur in the early stages of the fatigue process.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Geological
Vikram Vishal, Debanjan Chandra
Summary: This study uses digital volume correlation and quantitative image analysis to investigate the evolution and propagation of cracks in coal. The results demonstrate the crucial role of organic matter in guiding and initiating cracks in coal. Constructive interference between tensile and shear crack systems enhances permeability and reduces tortuosity. Moreover, the tortuosity of the cracks decreases exponentially, while permeability and crack volume fraction increase exponentially with increasing load.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Electrical & Electronic
Ankita Roy, Amey Luktuke, Nikhilesh Chawla, Kumar Ankit
Summary: This study presents a method that combines material thermodynamics with diffusional kinetics to predict the growth characteristics of Cu6Sn5 in Cu-Sn alloy. The calculations indicate the limited role of IMC/Sn interfacial curvature in determining the rate at which the IMC layer thickens.
JOURNAL OF ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Weiheng Xu, Rahul Franklin, Dharneedar Ravichandran, Mohammed Bawareth, Sayli Jambhulkar, Yuxiang Zhu, Mounika Kakarla, Faizan Ejaz, Beomjin Kwon, Mohammad K. Hassan, Maryam Al-Ejji, Amir Asadi, Nikhilesh Chawla, Kenan Song
Summary: This research focuses on a new patterning technique to create ordered nanoparticle assembly in layered composite fibers. By using innovative tool design, unique material combinations, and precise rheology control, distinct layers can be retained during fiber spinning. This approach presents an unprecedented fiber manufacturing platform for controlled layer dimensions and nanoparticle manipulations, with potential applications in various fields including structural supports, heat exchangers, electrical conductors, sensors, actuators, and soft robotics.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Zoology
Clint A. Penick, Grace Cope, Swapnil Morankar, Yash Mistry, Alex Grishin, Nikhilesh Chawla, Dhruv Bhate
Summary: Biodiversity provides a rich source of innovation for bio-inspired design, but considering the large number of species can be overwhelming. The champion adapter approach, although beneficial, tends to focus on a narrow set of popular models while neglecting the majority of species. The comparative method, on the other hand, leverages biodiversity by drawing inspiration from a wide range of species.
INTEGRATIVE AND COMPARATIVE BIOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Tsimur Davydzenka, Daniel Sinclair, Nikhilesh Chawla, Pejman Tahmasebi
Summary: This study discusses the application of X-ray micro-computed tomography imagery in materials science, as well as the challenge of time-intensive segmentation of large data sets. Researchers propose a machine learning method to improve segmentation accuracy by increasing variations in training images, significantly enhancing accuracy in X-ray microscopy imaging.
MATERIALS CHARACTERIZATION
(2022)
Article
Engineering, Manufacturing
Athul Rajeev, Alex Grishin, Varun Agrawal, Bharath Santhanam, Derek Goss, Sridhar Niverty, Grace Cope, Clint A. Penick, Nikhilesh Chawla, Vikram Shyam, Ezra McNichols, Dhruv Bhate
Summary: This study investigates the influence of corner radius on the performance of regular hexagonal honeycomb under compression loading. The results show that corner radii increase the effective modulus and reduce maximum corner stress, but there exists an optimum corner radius beyond which stresses rise again. The presence of a corner radius shifts the failure mechanism from nodal fracture to plastic hinging, providing benefits for energy absorption applications.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Materials Science, Multidisciplinary
Daniel Sinclair, Sridhar Niverty, Nikhilesh Chawla
Summary: X-ray microcomputed tomography was used to observe the localized corrosion of an AA7075-T651 sample immersed in a 3.5 wt% NaCl solution. Pitting initiated at cathodic intermetallic inclusions and showed a start-and-stop trend due to decoupling effects. Samples with higher extent of cold rolling had a finer and more homogeneous distribution of inclusions, leading to increased pit depth. Alternate immersion with intermittent drying destabilized the passive layer, while continuous immersion for 20 days produced a uniform and protective corrosion product layer.
Article
Engineering, Electrical & Electronic
Tarun Amla, Nikhilesh Chawla
Summary: Devices used in power electronics, such as GaN, SiC, and other wide band gap semiconductors, have high operating temperatures and require special die attach materials. Traditional solder materials are not suitable due to their limitations. Sintered nano-silver with high thermal and electrical conductivity is a good alternative. High thermomechanical stresses in these devices affect their performance and reliability. Virtual testing using finite element analysis is an effective method to overcome the challenges of building test vehicles and making predictions. The paper demonstrates a detailed reliability assessment using FEA simulations and an analytical fatigue reliability model.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
John A. Wu, Amey Luktuke, Nikhilesh Chawla
Summary: With the development of heterogeneous integration packaging, there is a growing demand for solders with ideal mechanical properties and melting temperatures. Sn-Ag-Cu (SAC) solders are a reliable alternative to PbSn solders, offering ideal mechanical properties and low melting points when alloyed with other elements. SAC-3Bi solder is found to have bismuth precipitation at room temperature after being aged, specifically on the exposed surface. Different cooling rates during solder solidification affect the coarsening rates, indicating varying diffusion and nucleation rates influenced by the cooling process.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Engineering, Biomedical
Swapnil K. Morankar, Yash Mistry, Dhruv Bhate, Clint A. Penick, Nikhilesh Chawla
Summary: In this study, the unique layered structure of the fibers from deep-sea sponge Euplectella aspergillum was investigated using in situ tensile testing and fractography. The real-time observation revealed that the failure of fibers initiated from the surface and propagated towards the center through successive layers. The concentric layers sacrificed themselves to protect the central core through various toughening mechanisms. These findings provide insights for the design of architected materials for load-bearing applications.
ACTA BIOMATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Amey Luktuke, Arun Sundar Sundaram Singaravelu, Arun Mannodi-Kanakkithodi, Nikhilesh Chawla
Summary: The composition of alloying elements in Sn-rich solder is crucial for the performance of solder joints in electronic packages. This study investigates the impact of small additions of Indium (In) on the properties of pure Sn solder. Various characterization techniques reveal insights into the microstructure and interfacial intermetallic (IMC) layer formation, as well as the mechanisms behind the changes in these properties due to the addition of In.
Article
Materials Science, Multidisciplinary
Swapnil Morankar, Ankit Kumar, Amey Luktuke, Nikhilesh Chawla
Summary: The properties of the deep-sea sponge Euplectella aspergillum's spicules were investigated using in situ nanoindentation in different water conditions. The layered regions of the spicules were found to be softer and more compliant than the central core. Exposure to water resulted in a decrease in stiffness and hardness of the layered regions, indicating the influence of hydration and plasticization on the mechanical behavior. These findings provide insight into the role of spicule architecture and its constituents in determining mechanical properties in a water environment.
Meeting Abstract
Zoology
G. C. Cope, D. Goss, N. Chawla, A. Grishin, D. Bhate, C. Penick
INTEGRATIVE AND COMPARATIVE BIOLOGY
(2023)
Meeting Abstract
Zoology
C. A. Penick, G. Cope, D. Goss, A. Grishin, N. Chawla, D. Bhate
INTEGRATIVE AND COMPARATIVE BIOLOGY
(2023)
Article
Engineering, Manufacturing
Paul Paradise, Shawn Clonts, Sridhar Niverty, Mandar Shinde, Austin Suder, Tyler Smith, Thomas Broderick, Mark Benedict, Nikhilesh Chawla, Dhruv Bhate
Summary: This study examines the measurement capabilities of four different methods for thin-wall structures and finds that the standard micrometer is inaccurate, while the point micrometer and blue light scanning are reliable. Variations in section area for thin specimens can contribute to mechanical failure.
MANUFACTURING LETTERS
(2022)
Article
Engineering, Manufacturing
Paul Paradise, Shawn Clonts, Sridhar Niverty, Mandar Shinde, Austin Suder, Tyler Smith, Thomas Broderick, Mark Benedict, Nikhilesh Chawla, Dhruv Bhate
Summary: This study examined the measurement capabilities of four different methods for thin-wall structures, showing that point micrometer and blue light 3D scanning are reliable measurement methods while standard micrometer is not. The variation in cross-sectional area of thin specimens contributes to failure initiation at lower strengths and explains mechanical debits observed with reductions in thickness.
MANUFACTURING LETTERS
(2022)
