Effects Of Stress Loading Research Articles

Effect of stress loading on hot salt corrosion behavior of TiAlTaN/CrAlN multilayer coatings

The hot salt corrosion behavior of TiAlTaN coating and TiAlTaN/CrAlN multilayer coatings with different modulation periods under external stress condition were studied. The complex stress distribution on the specimen surface was obtained by designing a double-sided notched tensile specimen, and then the hot salt stress corrosion test was carried out at 500 °C for 120 h. The TiAlTaN monolayer coating had obvious stress cracking under stress loading, while the TiAlTaN/CrAlN multilayer coatings showed good resistance to hot salt stress corrosion crack even under high stress. The performance improvement was attributed to the role of multilayer interfaces in inhibiting microcrack growth and diffusion of the corrosion medium into the coating. In particular, the TiAlTaN/CrAlN-10 multilayer coating with smaller modulation period not only had better hot salt corrosion resistance, but also showed excellent resistance to crack propagation under stress loading, forming effective protection for the titanium alloy substrate.

Effect of stress on corrosion behavior of martensitic and austenitic steels in supercritical carbon dioxide at 550 °C and 20 MPa

Corrosion of alloys in supercritical carbon dioxide (S-CO2) Brayton cycle power generation systems is a critical issue. In this study, we investigated the corrosion behaviors of martensitic AISI 616 and austenitic AISI 304 exposed to S-CO2 at 550 °C and 20 MPa. The effect of stress loading on the corrosion behavior was studied. A 9-μm-thick double-layer oxide with an outer layer of Fe3O4 and an inner layer of (Fe, Cr)-rich oxide was formed on the surface of the AISI 616. When stress was applied, the oxide layer thickness increased significantly to 15 µm. Stress loading thus promoted carbon deposition, accelerated the oxidation rate, and increased oxide thickness. AISI 304 generated a monolayer of (Fe, Cr)-rich oxide that was much thinner than that of AISI 616 owing to its high Cr content. In addition, the effect of stress on the corrosion of AISI 304 was weaker than that of AISI 616.

Terahertz data analytics-based bonding interface damage characterization in a multilayer structural composites under cyclic loading

Adhesively-bonded composite structures are under various environmental loads during their service life. Therefore, it is imperative to monitor the evolution of the bonding interfaces under loading to evaluate the bonding properties of the composite structures. A terahertz (THz) quantitative characterization method is proposed based on the scale invariant feature transform (SIFT) image matching algorithm. The terahertz data for the bonding interface before and after loading were obtained using a terahertz time-domain spectroscopy system along with the flight time imaging of the bonding interface. The imaging results of the bonding interface before and after loading were matched by SIFT image processing technology, and the THz flight time difference was obtained using differential calculations to characterize the thickness change of the bonding interface. Furthermore, the initiation and development of interface damage were studied, and the changes in the bonding interface thickness and debonding damage state under the cyclic loading tests were analyzed, providing information on the growth of the damaged area and damage severity. The results show that the proposed method can ultimately realize the characterization of the thickness changes and the evolution of the debonding damages at the interface of the bonded composite structures under cyclic stress, thus circumventing the shortcomings of the conventional damage-evolution characterization methods. The findings can also provide helpful insights into the effect of stress load on the bonding interface damage evolution for the studied system.

Microstructural Evolution of the TLP Joints of RAFM Steel during Aging and Creep

In this study, transient liquid-phase (TLP) bonding was adopted to obtain a reliable reduced-activation ferritic/martensitic (RAFM) steel joint with Fe-Si-B amorphous foil. The aging tests and creep tests of the TLP joints were carried out at 550 °C to study the microstructural evolution in the service process. The effect of stress loading on the microstructural evolution of the TLP joint was investigated. The results show that creep fractures in the TLP joints occur in the base material. The main factors affecting the creep performance of TLP joints are the recovery of substructures and the coarsening and deformation of martensitic laths. In addition, the M23C6 carbides in the base material were coarser than in the weld zone. Compared with aging samples and creep samples undergoing the same test temperature, the dislocation density in the isothermal solidification zone (ISZ) increased significantly with increases in the stress level. Furthermore, it is worth noting that the microstructure of the weld zone changed from large-sized ferrite to a mixed, fine microstructure of ferrite and martensite, which increases the heat resistance of the TLP joints, and thus results in creep fractures in the base metal.

Effect of stress loading combined with fluido-therapy on CRPS-1 in stroke hemiplegics.

Effect of stress loading combined with fluido-therapy on CRPS-1 in stroke hemiplegics.

Stress load during childhood affects psychopathology in psychiatric patients

BackgroundChildhood stress and trauma have been related to adult psychopathology in different psychiatric disorders. The present study aimed at verifying this relationship for stressful experiences during developmental periods by screening stress load across life in adult psychiatric inpatients with different diagnoses compared to healthy subjects. In addition, a relationship between the amount of adverse experiences and the severity of pathology, which has been described as a 'building block' effect in posttraumatic stress disorder (PTSD), was explored for non-traumatic events in psychiatric disorders other than PTSD.Methods96 patients with diagnoses of Major Depressive Disorder (MDD), schizophrenia, drug addiction, or personality disorders (PD) and 31 subjects without psychiatric diagnosis were screened for adverse experiences in childhood (before the age of six years), before onset of puberty, and in adulthood using the Early Trauma Inventory and the Posttraumatic Stress Diagnostic Scale. Effects of stress load on psychopathology were examined for affective symptoms, PTSD, and severity of illness by regression analyses and comparison of subgroups with high and low stress load.ResultsHigh stress load in childhood and before puberty, but not in adulthood, was related to negative affect in all participants. In patients, high stress load was related to depressive and posttraumatic symptoms, severity of disorder, and the diagnoses of MDD and PD.ConclusionResults support the hypothesis of stress-sensitive periods during development, which may interact with genetic and other vulnerability factors in their influence on the progress of psychiatric disorders. A 'dose' effect of stress load on the severity of psychopathology is not restricted to the relationship between traumata and PTSD.

ストレス負荷時における血中L-アルギニンレベルについて

ストレス負荷時における血中L-アルギニンレベルについて