Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (6)

Search Parameters:
Keywords = microtensions

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
12 pages, 2245 KB  
Article
Analysis of Fatigue Life After Application of Compressive Microstresses on the Surface of Components Manufactured by Metal Injection Molding
by Jorge Luis Braz Medeiros, Luciano Volcanoglo Biehl and Ismael Cristofer Baierle
Surfaces 2025, 8(1), 19; https://doi.org/10.3390/surfaces8010019 - 14 Mar 2025
Viewed by 910
Abstract
The metal injection molding (MIM) manufacturing process has made relevant advances for applications in components with complex geometries, small dimensions, and high production volumes. New technologies such as hot isostatic pressing (HIP), uniform polymer extraction, and sintering with reduced temperature variations improve metallurgical [...] Read more.
The metal injection molding (MIM) manufacturing process has made relevant advances for applications in components with complex geometries, small dimensions, and high production volumes. New technologies such as hot isostatic pressing (HIP), uniform polymer extraction, and sintering with reduced temperature variations improve metallurgical and mechanical properties. However, there are still knowledge gaps in understanding these technologies and the behavior of catalytic low-alloy steels obtained by the MIM process and cyclic applications. This study aims to analyze the behavior of Catamold 100Cr6 steel subjected to quenching and tempering heat treatment in different microhardness ranges and the effect of compressive stresses on the samples obtained by polishing using ceramic microchips. The samples were characterized using optical microscopy, scanning electron microscopy, an EDS microprobe, and X-ray diffraction and subjected to elastic return cycling and an experimental device developed to apply a 19° bending angle. The findings show a significant increase in fatigue life due to the compressive stresses (up to—430 MPa) generated by the reduction in retained austenite and surface plastic microdeformation, indicating the effectiveness of 100Cr6 Catamold steel in cyclic applications. Full article
Show Figures

Figure 1

18 pages, 286 KB  
Article
Essential Work in the U.S. during COVID-19: Navigating Vulnerability–Sustainability Tensions
by Astrid M. Villamil and Suzy D’Enbeau
Sustainability 2021, 13(19), 10665; https://doi.org/10.3390/su131910665 - 25 Sep 2021
Cited by 9 | Viewed by 3401
Abstract
The COVID-19 pandemic affected every functioning system in the United States. Workers deemed “essential” faced multiple threats to their well-being that quickly led to acute symptoms of anxiety, depression, burnout, and overall exhaustion, and organizations were challenged to devise employee protocols to maintain [...] Read more.
The COVID-19 pandemic affected every functioning system in the United States. Workers deemed “essential” faced multiple threats to their well-being that quickly led to acute symptoms of anxiety, depression, burnout, and overall exhaustion, and organizations were challenged to devise employee protocols to maintain sustainability. This qualitative study takes a tension-centered approach to discern how “essential workers” in the United States navigated this tenuous work landscape, particularly with regard to emotional work and workplace dignity. We conducted 19 semi-structured in-depth interviews with essential workers during COVID-19. Our constant comparative analysis of the data identified a macro-tension between vulnerability and sustainability that was revealed through two micro-tensions: (a) essential work as instrumental and disposable, and (b) workplace dignity as recognized and transgressed. We unpack the emotional responses enmeshed in these micro-tensions and situate our findings at the intersection of organizational sustainability, emotional work and workplace dignity. We offer theoretical and practical implications for essential workers and organizations. Full article
(This article belongs to the Special Issue Emotional Communication, Organizations, and Sustainability)
12 pages, 3531 KB  
Article
Gradient Enhanced Strain Hardening and Tensile Deformability in a Gradient-Nanostructured Ni Alloy
by Xinlai An, Weikang Bao, Zuhe Zhang, Zhouwen Jiang, Shengyun Yuan, Zesheng You and Yong Zhang
Nanomaterials 2021, 11(9), 2437; https://doi.org/10.3390/nano11092437 - 18 Sep 2021
Cited by 5 | Viewed by 2993
Abstract
Gradient-nanostructured material is an emerging category of material with spatial gradients in microstructural features. The incompatibility between gradient nanostructures (GNS) in the surface layer and coarse-grained (CG) core and their roles in extra strengthening and strain hardening have been well elucidated. Nevertheless, whether [...] Read more.
Gradient-nanostructured material is an emerging category of material with spatial gradients in microstructural features. The incompatibility between gradient nanostructures (GNS) in the surface layer and coarse-grained (CG) core and their roles in extra strengthening and strain hardening have been well elucidated. Nevertheless, whether similar mechanisms exist within the GNS is not clear yet. Here, interactions between nanostructured layers constituting the GNS in a Ni alloy processed by surface mechanical rolling treatment were investigated by performing unique microtension tests on the whole GNS and three subdivided nanostructured layers at specific depths, respectively. The isolated nanograined layer at the topmost surface shows the highest strength but a brittle nature. With increasing depths, isolated layers exhibit lower strength but enhanced tensile plasticity. The GNS sample’s behavior complied more with the soft isolated layer at the inner side of GNS. Furthermore, an extra strain hardening was found in the GNS sample, leading to a greater uniform elongation (>3%) as compared to all of three constituent nanostructured layers. This extra strain hardening could be ascribed to the effects of the strain gradients arising from the incompatibility associated with the depth-dependent mechanical performance of various nanostructured layers. Full article
(This article belongs to the Special Issue Gradient Nanograined Materials)
Show Figures

Figure 1

11 pages, 34659 KB  
Article
A Method for Rapid Prediction of Edge Defects in Cold Roll Forming Process
by Zhijuan Meng, Yanan Fang and Lidong Ma
Mathematics 2021, 9(16), 1902; https://doi.org/10.3390/math9161902 - 10 Aug 2021
Cited by 6 | Viewed by 2884
Abstract
In order to implement rapid prediction of edge defects in the cold roll forming process, a new analytical method based on the mean longitudinal strain of the racks is presented. A cubic spline curve with the parameters of the cumulative chord length is [...] Read more.
In order to implement rapid prediction of edge defects in the cold roll forming process, a new analytical method based on the mean longitudinal strain of the racks is presented. A cubic spline curve with the parameters of the cumulative chord length is applied to fit the corresponding points and center points of different passes, and fitting curves are obtained. As the cold roll forming is micro-tension forming, the tensions between racks are ignored. Then the mean longitudinal strains between racks are obtained. By comparing the mean longitudinal strain between racks and the yield strain of the material, we can judge whether there are defects at the edges. Finally, the reasonableness of this method is illustrated and validated by an example. With this method, the roll forming effect can be quickly predicted, and the position where a greater longitudinal strain occurred can be determined. In order to prevent the defects, the deformation angles need to be modified when the result is beyond the yield strain. To further prove the correctness of the theory, the results of the analytical method are compared with the ones of the non-linear finite element software ABAQUS. The analytical results have the same trend as the finite element results. This method can provide useful guidance to the actual design process. Full article
Show Figures

Figure 1

12 pages, 5412 KB  
Article
Current-Induced Ductility Enhancement of a Magnesium Alloy AZ31 in Uniaxial Micro-Tension Below 373 K
by Xinwei Wang, Antonio J. Sánchez Egea, Jie Xu, Xianyu Meng, Zhenlong Wang, Debin Shan, Bin Guo and Jian Cao
Materials 2019, 12(1), 111; https://doi.org/10.3390/ma12010111 - 31 Dec 2018
Cited by 20 | Viewed by 4818
Abstract
The size effects in metal forming have been found to be crucial in micro-scale plastic deformation or micro-forming processes, which lead to attenuation of the material’s formability due to the increasing heterogeneity of the plastic flow. The use of an electric field during [...] Read more.
The size effects in metal forming have been found to be crucial in micro-scale plastic deformation or micro-forming processes, which lead to attenuation of the material’s formability due to the increasing heterogeneity of the plastic flow. The use of an electric field during micro-scale plastic deformation has shown to relieve size effects, enhance the material’s formability, modify the microstructure, etc. Consequently, these electric-assisted (EA) micro-forming processes seem to bring many potential benefits that need to be investigated. Accordingly, here we investigated the influence of an electric field on the size effects to describe the fracture behavior in uniaxial micro-tension tests of an AZ31 alloy with various grain sizes. In order to decouple the thermal-mechanical and microstructure changes, room temperature (RT), oven-heated (OH), air-cooled (AC), and EA uniaxial micro-tension tests were conducted. The size effects contribution on the fracture stress and strain showed a similar trend in all the testing configurations. However, the smallest fracture stresses and the largest fracture strains were denoted in the EA configuration. EBSD examination shows that current-induced dynamic recrystallization (DRX) and texture evolution could be negligible under the studied conditions. The kernel average misorientation (KAM) maps give the larger plastic deformation in the EA specimens due to the reduction of plastic micro-heterogeneity. Finally, the fracture morphology indicates that the current-induced ductility enhancement may be attributed to the arrest of micro-crack propagation and the inhibition of void initiation, growth, and coalescence caused by lattice melting and expansion. Full article
Show Figures

Figure 1

10 pages, 2475 KB  
Article
Equimolar Yttria-Stabilized Zirconia and Samaria-Doped Ceria Solid Solutions
by Reginaldo Muccillo, Daniel Z. De Florio and Eliana N. S. Muccillo
Ceramics 2018, 1(2), 343-352; https://doi.org/10.3390/ceramics1020027 - 22 Nov 2018
Cited by 2 | Viewed by 4310
Abstract
Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria—8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria—SDC20) ceramic powders were prepared by attrition milling to form an [...] Read more.
Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria—8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria—SDC20) ceramic powders were prepared by attrition milling to form an equimolar powder mixture, followed by uniaxial and isostatic pressing. The pellets were quenched to room temperature from 1200 °C, 1300 °C, 1400 °C and 1500 °C to freeze the defects configuration attained at those temperatures. X-ray diffraction analyses, performed in all quenched pellets, show the evolution of the two (8YSZ and SDC20) cubic fluorite structural phases to a single phase at 1500 °C, identified by Rietveld analysis as a tetragonal phase. Impedance spectroscopy analyses were carried out in pellets either quenched or slowly cooled from 1500 °C. Heating the quenched pellets to 1000 °C decreases the electrical resistivity while it increases in the slowly cooled pellets; the decrease is ascribed to annealing of defects created by lattice micro-tensions during quenching while the increase to partial destabilization of the tetragonal phase. Full article
(This article belongs to the Special Issue Novel Processing Routes of Ceramics for Functional Applications)
Show Figures

Graphical abstract

Back to TopTop