scholarly journals Determination of Stress-Free Lattice Spacing (D₀) for Residual Stress Relaxation Measurement in Ni-based Superalloys by Neutron Diffraction

2020 ◽  
Author(s):  
Yan Chen ◽  
Ke An ◽  
Alexandru Stoica
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Neutron Diffraction ◽  
Lattice Spacing ◽  
Free Lattice ◽  
Relaxation Measurement ◽  
Residual Stress Relaxation

Methods for obtaining the strain-free lattice parameter when using diffraction to determine residual stress

2007 ◽  
Vol 40 (5) ◽  
pp. 891-904 ◽  
Author(s):  
P. J. Withers ◽  
M. Preuss ◽  
A. Steuwer ◽  
J. W. L. Pang
Keyword(s):  
Residual Stress ◽  
Lattice Spacing ◽  
Lattice Parameter ◽  
The State ◽  
The Body ◽  
Free Lattice ◽  
Stress Measurements

The determination of residual stress by diffraction depends on the correct measurement of the strain-free lattice spacing d_{hkl}^0, or alternatively the enforcement of some assumption about the state of strain or stress within the body. It often represents the largest uncertainty in residual stress measurements since there are many ways in which the strain-free lattice spacing can vary in ways that are unrelated to stress. Since reducing this uncertainty is critical to improving the reliability of stress measurements, this aspect needs to be addressed, but it is often inadequately considered by experimenters. Many different practical strategies for the determining of d_{hkl}^0 ordrefhave been developed, some well known, others less so. These are brought together here and are critically reviewed. In practice, the best method will vary depending on the particular application under consideration. Consequently, situations for which each method are appropriate are identified with reference to practical examples.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

scholarly journals Prediction of Residual Stress Relaxation of Shot Peened 2024-T351 Aluminum Alloy: Part 1

2011 ◽  
Vol 462-463 ◽  
pp. 1355-1360
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Applied Load ◽  
Cold Work ◽  
Cyclic Tests ◽  
Initial State ◽  
Loading Cycle ◽  
Residual Stress Relaxation ◽  
Alloy Part

It is important to account for residual stress relaxation phenomenon in the design of the component. Specimens of 2024-T351 aluminium alloy were used in this study. The specimens were shot peened under three different shot peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10000 cycles. Residual stresses, microhardness and the cold work percentage were measured at initial state and after each loading cycle for the three shot peening intensities and for the two loads. The study revealed that most of the drop in the residual stress, microhardness and cold work happened in the first cycle are dependent on the applied load.

Long Term Stability Evaluation of Stress Improvement Effect on Ni-Based Alloy Welds by Various Residual Stress Improvement Methods

2021 ◽  
Vol 1016 ◽  
pp. 819-825
Author(s):  
Li Na Yu ◽  
Kazuyoshi Saida ◽  
Masahito Mochizuki ◽  
Kazutoshi Nishimoto ◽  
Naoki Chigusa
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Stress Relaxation ◽  
Compressive Residual Stress ◽  
Alloy 600 ◽  
Pressurized Water ◽  
Residual Stress Relaxation ◽  
Temperature Environment ◽  
Water Reactors ◽  
High Temperature Environment

Stress corrosion cracking (SCC) is one of serious aging degradation problems for the Alloy 600 components of pressurized water reactors (PWRs). In order to prevent SCC, various methods such as water jet peening (WJP), laser peening (LP), surface polishing have been used to introduce compressive stresses at the surfaces of the PWR components. However, it has been reported that such compressive residual stress introduced by these methods might be relaxed during the practical operation, because of high temperature environment. In this study, the hardness reduction behavior of the Alloy 600 processed by LP, Buff and WJP in the thermal aging process has been investigated to estimate the stability of the residual stress improving effect by each method, based on the fact that there is a correlation between the compressive residual stress relaxation and the decrease of hardness. The behavior of the residual stress relaxation in the processed materials in the high temperature environment has been discussed with kinetic analysis.

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