Measurement of Microscale Residual Stresses in Single-Phase Ceramics and the Relationship Among Residual Stress, Ordering Degree, and Microwave Dielectric Loss

2020 ◽  
Author(s):  
Jianli Qiao ◽  
Lingxia Li ◽  
Wei Peng ◽  
Tao Xue ◽  
Mingkun Du
Keyword(s):  
Residual Stress ◽  
Dielectric Loss ◽  
Residual Stresses ◽  
Single Phase ◽  
Microwave Dielectric ◽  
Ordering Degree ◽  
The Relationship

An analysis of shot peening

1983 ◽  
Vol 18 (2) ◽  
pp. 95-100 ◽  
Author(s):  
D A Hills ◽  
R B Waterhouse ◽  
B Noble
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Experimental Evidence ◽  
Contact Pressure ◽  
Shot Peening ◽  
Pressure Loading ◽  
The Relationship

It is shown that the residual stresses obtained during shot-peening are directly proportional to the treated material's hardness, and that the depth of material influenced depends on the velocity of approaching shot. The relationship between the shot size and depth hardened is developed, and experimental evidence is provided to verify the major points of the analysis. Useful curves, enabling the variation of residual stress with depth to be estimated, are included, and this enables the shot-peening treatment to be matched to alleviate any subsequent contact-pressure loading that the material may experience during service.

scholarly journals Experimental Measurement of Residual Stress Distribution in Rail Specimens Using Ultrasonic LCR Waves

2021 ◽  
Vol 11 (19) ◽  
pp. 9306
Author(s):  
Young-In Hwang ◽  
Geonwoo Kim ◽  
Yong-Il Kim ◽  
Jeong-Hak Park ◽  
Man-Yong Choi ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Residual Stress Distribution ◽  
Material Surface ◽  
Arrival Times ◽  
Effective Depth ◽  
The Difference ◽  
The Relationship

Longitudinal critically refracted (LCR) waves are considered bulk longitudinal waves and penetrate into an effective depth beneath the surface parallel to the material surface. Such LCR waves can be employed to measure residual stresses because the acoustoelastic effect is the basis for ultrasonic residual stress measurements. This effect is described by the relationship between change of wave travel time and stress applied when such waves propagate in a stressed medium. In this paper, stresses applied in a rail were evaluated by using a developed LCR probe. With this transducer, it was verified how the difference in the arrival times of the LCR waves showed a trend as the tensile stresses increased. The acoustoelastic coefficients were calculated using the relationship between the stresses and the travel times, and the residual stresses of the used rails were measured using these coefficients. In addition, the difference in residual stress distribution according to the characteristics of the wheel-rail contact surface was analyzed from the obtained residual stress value. It was concluded that this non-destructive evaluation technique using LCR waves could be employed for accurate stress measurement of rails because differences in stress applied to the rail can be detected.

The Study of the Relationships between Material Properties and Welding Residual Stresses

2010 ◽  
Vol 97-101 ◽  
pp. 703-708 ◽  
Author(s):  
Yao Long Tsai ◽  
Chin Chun Chang ◽  
Chang Pin Chou
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Material Properties ◽  
Steel Plate ◽  
Prediction Equation ◽  
Welding Residual Stress ◽  
Finite Element Analyses ◽  
Welded Steel ◽  
Stress Zone ◽  
The Relationship

The objective of this study is to explore the influence of the steel’s material properties on the distribution of welding residual stresses of the butt-welded steel plate. First, S15C carbon steel’s material properties are varied in this study to calculate the corresponding welding residual stress by carrying out 3D finite element analyses. Results show the maximum longitudinal tensile residual stresses increase linearly with increasing thermal expansion coefficient and increasing yield stress. The length of the tensile residual stress zone decreases linearly with increasing thermal conductivity. Finally, based on the relationship between material properties and welding residual stresses, a useful prediction equation is developed and verified in this study.

scholarly journals Effect of as-deposited residual stress on transition temperatures of VO2 thin films

2004 ◽  
Vol 19 (8) ◽  
pp. 2306-2314 ◽  
Author(s):  
Kuang Yue Tsai ◽  
Tsung-Shune Chin ◽  
Han-Ping D. Shieh ◽  
Cheng Hsin Ma
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Residual Stresses ◽  
Transition Temperatures ◽  
X Ray ◽  
Core Electrons ◽  
The Difference ◽  
Vo2 Thin Films ◽  
The Relationship ◽  
Oxygen Atoms

Transmittance loops upon thermal cycling of VO2 thin films were found to change among films with different fabrication conditions that lead to different transition temperatures (Tts) from that of a strain-free VO2 single crystal, 68 °C. The residual stresses in the films quantitatively determined from x-ray diffractometry were used to explain this variation. Electron spectroscopy for chemical analysis spectra showed that the difference in the binding energy of core electrons 2p1/2 and 2p3/2 of the vanadium atom are affected by residual stress and proportional to Tts of the films. The bond length between vanadium and oxygen atoms at room temperature varies with different residual stresses and, furthermore, affects the movements of both atoms during phase change (and hence the Tt of VO2 thin films). Residual stresses also affect the hysteresis span of the transmittance loop. The relationship between the residual stress of as-deposited VO2 films and the relative positions between vanadium and oxygen atoms are also delineated in detail.

Distribution of Residual Stresses in 1070 Single Phase Aluminium with Grain Size Gradient Formed by RBT Treatment

2013 ◽  
Vol 768-769 ◽  
pp. 343-350 ◽  
Author(s):  
Y. Enomoto ◽  
T. Nishimura ◽  
H. Sato ◽  
S.I. Tanaka
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Residual Stresses ◽  
Single Phase ◽  
Principal Stresses ◽  
Suitable Heat Treatment ◽  
Measured Stress ◽  
Spatial Grain ◽  
Distribution Of Stress ◽  
Xrd Method

Control of microstructure in single phase alloys are relatively limited and less way of expedient are available compared to multiphase alloys. Authors have attempted microstructural control of single phase alloy by formation of distribution of plastic strain and residual stresses. In this paper, residual stress distribution of 1070 single phase aluminium with RBT (Rotary Bending and Tensile) loading have been measured by 2D-XRD method. After suitable heat treatment, the alloy show spatial grain size distribution of 30-150μm. Measured stress tensor enabled by 2D-XRD method clealy show distribution of stress components of residual stress tensors and principal stresses. Direction of the principal stresses gradually rotate depending on position from center to radial direction. Even after annealing, the direction of principal axis agree with that of torsion during the RBT treatment. This results show possibility of control of microstructure in single phase material accomplished by introduction of gradual distribution of residual stresses.

TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite

1994 ◽  
Vol 52 ◽  
pp. 628-629
Author(s):  
J. Fang ◽  
H. M. Chan ◽  
M. P. Harmer
Keyword(s):  
Residual Stress ◽  
Single Phase ◽  
Stress Relief ◽  
Stress Recovery ◽  
Surface Residual Stress ◽  
Microscopic Mechanism ◽  
Sic Particles ◽  
Annealing Procedure ◽  
The Difference ◽  
Nano Size

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

2020 ◽  
pp. 095440892096401
Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
The Finite Element Method ◽  
Power Stations ◽  
Stainless Steel 304 ◽  
Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

scholarly journals Effects of Roughness on Stresses in an Oxide Scale Formed on a Superalloy Substrate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 479
Author(s):  
Yang Zhao ◽  
Fan Sun ◽  
Peng Jiang ◽  
Yongle Sun
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Residual Stresses ◽  
Oxide Scale ◽  
Rough Surface ◽  
Alumina Scale ◽  
Growth Stress ◽  
Oxide Growth ◽  
Substrate Thickness ◽  
Roughness Effect

The effects of surface roughness on the stresses in an alumina scale formed on a Fecralloy substrate are investigated. Spherical indenters were used to create indents with different radii and depths to represent surface roughness and then the roughness effect was studied comprehensively. It was found that the residual stresses in the alumina scale formed around the rough surface are almost constant and they are dominated by the curvature rather than the depth of the roughness. Oxidation changes the surface roughness. The edge of the indent was sharpened after oxidation and the residual stress there was released presumably due to cracking. The residual stresses in the alumina scale decrease with increase in oxidation time, while the substrate thickness has little effect, given that the substrate is thicker than the alumina scale. Furthermore, the effect of roughness on the oxide growth stress is analysed. This work indicates that the surface roughness should be considered for evaluation of stresses in coatings.

scholarly journals Influence of Preaging Temperature on the Indentation Strength of 3Y-TZP Aged in Ambient Atmosphere

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2767
Author(s):  
Ki-Won Jeong ◽  
Jung-Suk Han ◽  
Gi-Uk Yang ◽  
Dae-Joon Kim
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Low Temperature ◽  
Compressive Residual Stress ◽  
Yttria Stabilized Zirconia ◽  
Ambient Atmosphere ◽  
Aged Specimen ◽  
Stabilized Zirconia ◽  
M Phase ◽  
The Relationship

Yttria-stabilized zirconia (3Y-TZP) containing 0.25% Al2O3, which is resistant to low temperature degradation (LTD), was aged for 10 h at 130–220 °C in air. The aged specimens were subsequently indented at loads ranging from 9.8 to 490 N using a Vickers indenter. The influence of preaging temperature on the biaxial strength of the specimens was investigated to elucidate the relationship between the extent of LTD and the strength of zirconia restorations that underwent LTD. The indented strength of the specimens increased as the preaging temperature was increased higher than 160 °C, which was accompanied by extensive t-ZrO2 (t) to m-ZrO2 (m) and c-ZrO2 (c) to r-ZrO2 (r) phase transformations. The influence of preaging temperature on the indented strength was rationalized by the residual stresses raised by the t→m transformation and the reversal of tensile residual stress on the aged specimen surface due to the indentation. The results suggested that the longevity of restorations would not be deteriorated if the aged restorations retain compressive residual stress on the surface, which corresponds to the extent of t→m phase transformation less than 52% in ambient environment.

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