Effect of Thermal Cycling and Thermal Aging on the Mechanical Properties of, and Residual Stresses in, Ni-YSZ/YSZ Bi-Layers

2008 ◽  
pp. 383-391 ◽  
Author(s):  
E. Lara-Curzio ◽  
M. Radovic ◽  
R. M. Trejo ◽  
C. Cofer ◽  
T. R. Watkins ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Thermal Cycling ◽  
Thermal Aging

Effect of the Weld Joint Configuration on Stressed Components, Residual Stresses and Mechanical Properties

2014 ◽  
Vol 56 (4) ◽  
pp. 279-284 ◽  
Author(s):  
Bekir Çevik ◽  
Alpay Özer ◽  
Yusuf Özçatalbaş
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Weld Joint ◽  
Joint Configuration

scholarly journals Mechanical properties of rotary swaged steel components

2021 ◽  
Author(s):  
Dhia Charni ◽  
Svetlana Ortmann-Ishkina ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Jérémy Epp
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Strain Curve ◽  
Dynamic Mechanical Properties ◽  
Process Conditions ◽  
Forming Process ◽  
Rotary Swaging ◽  
Surface Residual Stresses ◽  
Near Net Shape ◽  
As Stress

AbstractThe radial infeed rotary swaging is widely used as a diameter reduction forming process of axisymmetric workpieces, improving the mechanical properties with excellent near net shape forming. In the present study, rotary swaging experiments with different parameter setups were performed on steel tubes and bars under different material states and several resulting property modifications were investigated such as stress-strain curve, hardness, fatigue strength and surface residual stresses. The results show a significant work hardening induced by the rotary swaging process and an improvement in the static and dynamic mechanical properties was observed. Furthermore, the hardness distribution was homogenous in the cross section of the rotary swaged workpieces. Moreover, depending on the process conditions, different residual stresses distribution were generated along the surface.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

scholarly journals Effect of Thermal Aging on the Mechanical Properties of High Tenacity Polyester Yarn

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1666
Author(s):  
Tsegaye Sh. Lemmi ◽  
Marcin Barburski ◽  
Adam Kabziński ◽  
Krzysztof Frukacz
Keyword(s):  
Mechanical Properties ◽  
Structural Change ◽  
Aging Time ◽  
Thermal Aging ◽  
Temperature Influence ◽  
Polyester Yarn ◽  
Textile Materials ◽  
Conveyor Belts ◽  
Effects Of Aging ◽  
Vulcanization Process

Textile materials produced from a high tenacity industrial polyester fiber are most widely used in the mechanical rubber goods industry to reinforce conveyor belts, tire cords, and hoses. Reinforcement of textile rubber undergoes a vulcanization process to adhere the textile materials with the rubber and to enhance the physio-mechanical properties of the product. The vulcanization process has an influence on the textile material being used as a reinforcement. In this work, the effects of aging temperature and time on the high tenacity polyester yarn’s mechanical and surface structural properties were investigated. An experiment was carried out on a pre-activated high tenacity polyester yarn of different linear densities, by aging the yarn specimens under various aging temperatures of 140, 160, 200, and 220 °C for six, twelve, and thirty-five minutes of aging time. The tensile properties and surface structural change in the yarns pre- and post-aging were studied. The investigation illustrates that aging time and temperature influence the surface structure of the fiber, tenacity, and elongation properties of the yarn. Compared to unaged yarn, an almost five times higher percentage of elongation was obtained for the samples aged at 220 °C for 6 min, while the lowest tenacity was obtained for the sample subjected to aging under 220 °C for 35 min.

scholarly journals Effect of Ion Irradiation on Nanoindentation Fracture and Deformation in Silicon Carbide

JOM ◽  
2021 ◽  
Author(s):  
Alexander J. Leide ◽  
Richard I. Todd ◽  
David E. J. Armstrong
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Compressive Residual Stresses

AbstractSilicon carbide is desirable for many nuclear applications, making it necessary to understand how it deforms after irradiation. Ion implantation combined with nanoindentation is commonly used to measure radiation-induced changes to mechanical properties; hardness and modulus can be calculated from load–displacement curves, and fracture toughness can be estimated from surface crack lengths. Further insight into indentation deformation and fracture is required to understand the observed changes to mechanical properties caused by irradiation. This paper investigates indentation deformation using high-resolution electron backscatter diffraction (HR-EBSD) and Raman spectroscopy. Significant differences exist after irradiation: fracture is suppressed by swelling-induced compressive residual stresses, and the plastically deformed region extends further from the indentation. During focused ion beam cross-sectioning, indentation cracks grow, and residual stresses are modified. The results clarify the mechanisms responsible for the modification of apparent hardness and apparent indentation toughness values caused by the compressive residual stresses in ion-implanted specimens.

Mechanical Properties of Epoxy Adhesive Under Thermal Aging and Their Chemical Degradation Behavior

2021 ◽  
Vol 21 (8) ◽  
pp. 4444-4449
Author(s):  
Bongjin Chung ◽  
Shin Sungchul ◽  
Jaeho Shim ◽  
Seongwoo Ryu
Keyword(s):  
Mechanical Properties ◽  
Thermal Aging ◽  
Photoelectron Spectroscopy ◽  
Thermal Exposure ◽  
Chain Scission ◽  
Epoxy Adhesive ◽  
Chemical Degradation ◽  
Adhesive Properties ◽  
Noticeable Reduction

Epoxy adhesive was analyzed under long term thermal aging and mechanical properties and chemical degradation were observed by X-ray photoelectron spectroscopy (XPS). Long term thermal exposure of epoxy causes a noticeable reduction in adhesive properties. We developed a predictive model of temperature and time dependent aging. The temperature dependent aging behavior of epoxy adhesive shows good agreement with conventional Arrhenius equations. Using XPS analysis, we also discovered a correlation between chemical degradation and the adhesive properties. Decay of C–C bonding ratio induced chain-scission of epoxy adhesive; increase of total numbers of C–O and C═O induced oxidation of epoxy adhesive during thermal exposure.

Effect of thermal cycling on the mechanical properties of carbon nanotubes reinforced copper matrix nanolaminated composites

2019 ◽  
Vol 739 ◽  
pp. 132-139 ◽  
Author(s):  
Jiapeng Liu ◽  
Ding-Bang Xiong ◽  
Yishi Su ◽  
Qiang Guo ◽  
Zhiqiang Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Cycling ◽  
Copper Matrix
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