Results 91 to 100 of about 52,231 (263)

Curvature inequalities and rigidity for constant mean curvature and spacetime constant mean curvature surfaces

We establish curvature inequalities and rigidity results for surfaces satisfying constant mean curvature type conditions in both Riemannian and Lorentzian geometry. In the Riemannian setting, we study constant mean curvature (CMC) surfaces. Building on the Christodoulou-Yau inequality $H^2\leq 16π/ |Σ|$ (with $H$ the mean curvature and $|Σ|$ the area ...
openaire   +2 more sources

Thermomechanical Fatigue and Creep–Fatigue Interaction of Inconel 718 Additively Manufactured by Laser Beam Powder Bed Fusion

Advanced Engineering Materials, EarlyView.
Thermomechanical fatigue tests of laser beam powder bed fusion (PBF‐LB) Inconel 718 show that the additively manufactured material reaches almost the lifetimes of conventionally‐rolled material under no‐dwell conditions. Introducing dwell times at the maximum temperature markedly reduces the lifetimes due to pronounced grain boundary sliding associated
Stefan Guth, Tomáš Babinský, Jan Lars Riedel, Wen Hao Kan, Aijun Huang, Martin Heilmaier, Ivo Šulák   +6 more
wiley   +1 more source

Combined Process‐ and Phase‐Field‐Simulation to Predict the Microstructure of Single‐Crystal Ni‐Based Superalloys

Advanced Engineering Materials, EarlyView.
A combined finite element and phase‐field approach predicts the evolution of microstructure during the directional solidification of Ni‐based superalloys. The model reveals how withdrawal rate, temperature gradient, and wall thickness control the dendrite spacing, highlighting the strong effect of surface regions in thin sections where dendrite growth ...
Sean Böhm, André B. Baldissera, Rainer Völkl, Uwe Glatzel   +3 more
wiley   +1 more source

Low‐Angle Grain Boundaries and Re‐Segregation in Single‐Crystalline Ni‐Base Superalloys

Advanced Engineering Materials, EarlyView.
This work demonstrates that Re‐segregation at low‐angle grain boundaries (LAGBs) in Ni‐base superalloys is influenced by misorientation angle. Advanced microscopy and atom probe tomography reveal that higher misorientation angles increases Re‐segregation.
Alireza B. Parsa, Aparna Saksena, Alesander Kostka, Pascal Thome, Felicitas Scholz, Alexandre Mussi, Christoph Somsen, Baptiste Gault, Jan Frenzel, Gunther Eggeler   +9 more
wiley   +1 more source

A Simplified Laminar Flow Model for the Pultrusion of Glass Fiber/Polyethylene Terephthalate Commingled Yarns

Advanced Engineering Materials, EarlyView.
A simplified thermoplastic pultrusion model is developed to predict thermal fields in glass fiber/polyethylene terephthalate (GF/PET) composites with reduced computational cost. By combining effective material homogenization, validation against literature data, and Gaussian‐process‐based optimization, the study reveals how heating limits, pulling speed,
Elder Soares, Nadège Bouchonneau, Christian Jochum, Donald Radford   +3 more
wiley   +1 more source

Rafting of Ni‐Based Superalloys Under Multiaxial Load as Understood by Phase‐Field Simulations and Critical Experiments

Advanced Engineering Materials, EarlyView.
Phase‐field simulations coupled with dislocation‐density‐based crystal plasticity modeling reproduce γ′ rafting behavior in single‐crystal Ni‐based superalloys under varied loading conditions. The model captures both macroscopic creep and microscopic morphology evolution, with results matching high‐temperature creep experiments.
Micheal Younan, David Bürger, Gunther Eggeler, Oleg Shchyglo, Ingo Steinbach, Muhammad Adil Ali   +5 more
wiley   +1 more source

Surfaces of Constant Mean Curvature in Euclidean 3-space Orthogonal to a Plane along its Boundary

Anais da Academia Brasileira de Ciências, 2002
We consider compact surfaces with constant nonzero mean curvature whose boundary is a convex planar Jordan curve. We prove that if such a surface is orthogonal to the plane of the boundary, then it is a hemisphere.
HINOJOSA PEDRO A.
doaj  

Complete spacelike hypersurfaces with positive r-th mean curvature in a semi-Riemannian warped product

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2015
In this paper, by supposing a natural comparison inequality on the positive r-th mean curvatures of the hypersurface, we obtain some new Bernstein-type theorems for complete spacelike hypersurfaces immersed in a semi-Riemannian warped product of constant
Wang Yaning, Liu Ximin
doaj   +1 more source

Time‐Dependent Oxidation and Scale Evolution of a Wrought Co/Ni‐Based Superalloy

Advanced Engineering Materials, EarlyView.
This study shows how a new wrought Co/Ni‐based superalloy resists oxidation at 800 ∘$^\circ$C. The oxide scale changes from rough, fast‐growing spinel to a dense, protective chromia–alumina layer. Atom probe analysis reveals tiny refractory‐rich bubbles at the interface that mark the transition to long‐term, diffusion‐controlled protection ...
Cameron Crabb, Zachary T. Kloenne, Samuel R. Rogers, Chi Hang Dominik Kwok, Mark C. Hardy, Michele S. Conroy, David Dye   +6 more
wiley   +1 more source

Karl Popper and the Mechanisms of Hydrogen Embrittlement

Advanced Engineering Materials, EarlyView.
Representation of the beginning of loss of ductility rather than embrittlement. Small concentrations of hydrogen in a diffusible form within iron are well‐established to harm the mechanical integrity of steels. There are theories that attempt to explain the pernicious role of hydrogen.
H. K. D. H. Bhadeshia
wiley   +1 more source