Showing 4 results for Sensitivity
Hosseini Sh., Arabi H., Tamizifar M., Zeyaei A.a.,
Volume 3, Issue 1 (6-2006)
Abstract
In this research, rotating bending fatigue test at minimum to maximum stress ratio of R=-1 was used for investigating the fatigue behavior of Ti-6Al-4V alloy. Both smooth and notched specimens, with elastic concentration factor, kt, of approximately 3.6 and 4.1 were used for this purpose.In addition, the effect of variation in ultimate tensile strength, UTS, on the fatigue behavior of this alloy was studied. S-N curves were drawn and the value of notch sensitivity was obtained or each case.The results showed that the presence of notch in Ti-6Al-4V alloy has a different amount of sensitivity when the notched specimens were subjected to high cycle fatigue (HCF) and low cycle fatigue (LCF) tests. However, the notch sensitivity of this alloy was shown generally to be much lower than steel alloys with similar UTS values. Thus, considering the high compatibility of this alloy with the body environment and its low sensitivity to notch, one can strongly recommend this alloy for use in biomedical application.
F. Hosseinabadi, A. Rezaee-Bazzaz, M. Mazinani, B. Mohammad Sadeghi,
Volume 17, Issue 1 (3-2020)
Abstract
An experimental–numerical methodology was used in order to study the microstructural effects on stress state dependency of martensitic transformation kinetics in two different TRIP800 low alloy multiphase steels. Representative volume elements extracted from actual microstructure have been utilized for simulating the mechanical behavior of mentioned steels. The mechanical behavior for each constituent phases required in the model has been taken out from those reported in the literature. A stress invariant based transformation kinetics law has been used to predict the martensitic phase transformation during deformation. Crystallographic and thermodynamic theories of martensitic phase transformation have been utilized for estimating the constant parameters of the kinetics law, in a recently performed investigation, but the sensitivity of the transformation to the stress state remained as an adjusting parameter. The results of the current work show that the stress state sensitivity of martensitic phase transformation in the investigated steels is microstructure-dependent and the value of this parameter is almost equal to half of the bainite volume fraction. Therefore, the volume fraction of bainite in the low-alloy multiphase TRIP800 steels can be used as a first postulation for the value of the martensitic phase transformation sensitivity to the stress state and the microstructure based model previously developed for calculating the mechanical behavior of the TRIP800 steels can be utilized as a virtual design tool for development of TRIP steels having specific mechanical properties.
Hossein Momeni, Sasan Ranjbar Motlagh,
Volume 21, Issue 3 (9-2024)
Abstract
The present work deals with the hot deformation behavior of commercial Nb alloy C-103 and its microstructure evolution during uniaxial compression tests in the temperature range of 700-1100 °C and the strain rate range of 0.001-0.4 s-1. Strain rate sensitivity, calculated from the compression tests data, was almost constant and showed a negative value in the temperature range of 700-900 °C but increased significantly beyond 900 °C. Dynamic strain aging was found to have a predominant effect up to 900 °C, beyond which dynamic recovery and oxidation influenced the compressive properties. The microstructure of the deformed samples showed indications of dynamic recrystallization within the high strain rate sensitivity domain and features of flow instability in the regime of low strain rate sensitivity. The 950–1000 °C temperature range and strain rate range of 0.001-0.1 s-1 were suggested as suitable hot deformation conditions. The constitutive equation was established to describe the alloy's flow behavior, and the average activation energy for plastic flow was calculated to be 267 kJ/mol.
Zainab T Hussain, Wasna’a M Abdulridha, Murooj A Abood, Farqad Saeed,
Volume 23, Issue 1 (3-2026)
Abstract
In this study, RF magnetron sputtering was employed to create titanium dioxide (TiO2) thin films doped with zirconium oxide (ZrO2) (TZO) onto quartz and silicon substrates at 100oC for the purpose of evaluating the effect of ZrO2 doping on the microstructural, electrical, optical and gas sensing properties of the TiO2 films. Different doping concentrations (0.0, 2.0 and 4.0 wt.%) were used to compare performances of the films with a thickness ranging between 147 nm to 178 nm. Structural and surface morphology characterizations of the prepared films were carried out by X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The surface morphology of the prepared TZO films showed a gradual reduction in the grain size while the doping concentration increased. The optical characteristics of the films also exhibited an increasing trend in the optical band gap with the rising ZrO2 concentration. TiO2 films showed an n-type conductivity as confirmed by Hall's measurement. The results of the gas sensing experiments revealed that the sensitivity of the TZO films for the detection of ethanol vapor increased with an increase in the concentration of ZrO2 dopant. Therefore, TZO film with 4.0 wt.% of ZrO2 could be used as an effective sensor for detecting ethanol vapor.
