Surface Yield Strength Gradient versus Residual Stress Relaxation of 7075 Aluminum Alloy

2010 ◽  
Vol 160-162 ◽  
pp. 241-246 ◽  
Author(s):  
Yong Hui Hu ◽  
Yun Xin Wu ◽  
Guang Yu Wang ◽  
Jun Kang Guo
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Yield Strength ◽  
Residual Stresses ◽  
Shot Peening ◽  
Fatigue Property ◽  
7075 Aluminum Alloy ◽  
Residual Stress Relaxation ◽  
Stress Coefficient

Different distributed residual stresses were introduced by quenching and two shot-peening treatments on 7075 aluminum alloy. The residual stress distributions and micro-hardness profiles in surface layers were measured. Pre-stress coefficient characterizing contribution of local residual stresses to local yield strength is introduced to analyze residual stress relaxation under cyclic loading. Load testing shows that re-distribution of residual stresses and proportional decrease of the pre-stress coefficient would occur in the non-uniform structural residual stresses introduced by quenching, while great stress relaxation and non-linear decrease of the pre-stress coefficient would occur in the uniform surface residual stresses introduced by shot-peening. Additionally, advantages of surface compressive residual stress and micro yield strength on anti-fatigue property and on restraining initiation and propagation of surface micro cracks should be considered in the usually conservative engineering design.

scholarly journals Micro-Hardness and Residual Stress Relaxation of 2024 T351 Aluminum Alloy

2011 ◽  
Vol 462-463 ◽  
pp. 343-348 ◽  
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi ◽  
Rizal Zahari
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Shot Peening ◽  
X Ray Diffraction ◽  
Initial State ◽  
Load Amplitude ◽  
Initial Residual Stress ◽  
Residual Stress Relaxation ◽  
Two Stages

The residual stress relaxation can be divided into two stages: The first cycle relaxation and the following cycles. In both stages, residual stress relaxed considerably from the initial state. The aim of this study is to investigate the residual stress relaxation and microhardness reduction after first and second cyclic load. A 2024 T351 aluminum alloy specimens were shot peened into three shot peening intensities. The fatigue test for first and second cyclic loads of two loads 15.5 kN and 30 kN was performed. The initial residual stress and residual stress after the first and second cycle stress was measured for the three shot peening intensities using X-ray diffraction. Microhardness test was performed for each specimen. The results showed that the residual stress relaxation for first cycle was reached more than 40% of the initial residual stress and it depends on the load amplitude, and microhardness decreased for the first cycle reached 22% and also it depended on load amplitude.

Polycrystal Plasticity Modeling of Cyclic Residual Stress Relaxation in Shot Peened Martensitic Gear Steel

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Rajesh Prasannavenkatesan ◽  
David L. McDowell
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Shot Peening ◽  
Cyclic Plasticity ◽  
Residual Stress Field ◽  
Residual Stress Relaxation ◽  
Gear Steel ◽  
Polycrystal Plasticity ◽  
Compressive Residual Stresses

Using a three-dimensional crystal plasticity model for cyclic deformation of lath martensitic steel, a simplified scheme is adopted to simulate the effects of shot peening on inducing initial compressive residual stresses. The model is utilized to investigate the subsequent cyclic relaxation of compressive residual stresses in shot peened lath martensitic gear steel in the high cycle fatigue (HCF) regime. A strategy is identified to model both shot peening and cyclic loading processes for polycrystalline ensembles. The relaxation of residual stress field during cyclic bending is analyzed for strain ratios Rε=0 and −1 for multiple realizations of polycrystalline microstructure. Cyclic microplasticity in favorably oriented martensite grains is the primary driver for the relaxation of residual stresses in HCF. For the case of Rε=−1, the cyclic plasticity occurs throughout the microstructure (macroplasticity) during the first loading cycle, resulting in substantial relaxation of compressive residual stresses at the surface and certain subsurface depths. The initial magnitude of residual stress is observed to influence the degree (percentage) of relaxation. Describing the differential intergranular yielding is necessary to capture the experimentally observed residual stress relaxation trends.

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.

Relaxation of Residual Stresses in Bearing Rings Based on the Optimal Geometric Setup of Equipment for Centerless Running

2019 ◽  
Vol 973 ◽  
pp. 183-188
Author(s):  
Albert V. Korolev ◽  
Andrei F. Balayev ◽  
Boris M. Iznairov
Keyword(s):  
Mathematical Model ◽  
Residual Stress ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Elastic Strain ◽  
New Approach ◽  
Technological Method ◽  
Residual Stress Relaxation ◽  
Bearing Rings

This paper discusses the technological method of residual stress relaxation of bearing rings by centerless running with cylindrical rolls. Described a new approach to relieve residual stresses by centerless running of elastically-deforming rolls on the basis of the geometrical setup of the equipment. It was found that geometrical setup of the equipment influences an elastic strain of parts and the degree of residual stress relaxation. We obtained a mathematical model for calculation of setup parameters to ensure the required variation value of elastic strain of the part. The results of experiments confirm the influence of the geometric setup on the magnitude of residual stress relaxation.

scholarly journals Investigation of residual stress, stress relaxation and work hardening effects induced by shot peening on the fatigue life of AA 6005-T6 aluminum alloy

2020 ◽  
Vol 6 (12) ◽  
pp. 1265i2 ◽  
Author(s):  
Martin Ferreira Fernandes ◽  
Marcelo Augusto Santos Torres ◽  
Maria da Penha Cindra Fonseca ◽  
Carlos Antonio Reis Pereira Baptista
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Work Hardening

scholarly journals Effects of Conventional and Severe Shot Peening on Residual Stress and Fatigue Strength of Steel AISI 1060 and Residual Stress Relaxation Due to Fatigue Loading: Experimental and Numerical Simulation

2020 ◽  
Author(s):  
Erfan Maleki ◽  
Gholam Hossein Farrahi ◽  
Kazem Reza Kashyzadeh ◽  
Okan Unal ◽  
Mario Gugaliano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Experimental Investigations ◽  
Residual Stress Relaxation ◽  
Severe Shot Peening

Abstract This study investigates and compares the effects of different shot peening treatments including conventional and severe shot peening on microstructure, mechanical properties, fatigue behavior, and residual stress relaxation of AISI 1060 steel. Shot peening treatments were applied with two Almen intensities of 17 and 21 A and a wide ranges of coverage (100%–1500%). Various microstructural observations were carried out to analyze the evolution of microstructure. Microhardness, residual stress and surface roughness measurements and also axial fatigue test were performed. Moreover, the extent of the residual stress relaxation during cyclic loading was investigated by means of XRD measurements. Furthermore, numerical simulation of residual stress relaxation due to fatigue loading was carried out and validated against experimental investigations. The comparison indicated a good agreement for the surface residual stress relaxation up to 100 cycles. The experimental results indicated the efficiency of severe shot peening processes in obtaining nanostructured surface layer and achieving superior mechanical properties and fatigue behavior. Also, residual stress measurements revealed that stress relaxation started with a high rate at the initial stages of loading and gradually increased at higher number of cycles which was lower in the case of severely shot peened samples compared to the conventionally treated ones. Graphic Abstract

Local Stress-Ratio Criterion for Incremental Hole-Drilling Measurements of Shot-Peening Stresses

2005 ◽  
Vol 128 (2) ◽  
pp. 193-201 ◽  
Author(s):  
J. P. Nobre ◽  
A. M. Dias ◽  
J. Gibmeier ◽  
M. Kornmeier
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Residual Stresses ◽  
Shot Peening ◽  
Local Stress ◽  
Hole Drilling ◽  
Surface Layers ◽  
Ratio Criterion ◽  
Incremental Hole Drilling ◽  
Hardened Surface

A criterion to evaluate the influence of the so-called plasticity effect on the final outcome of the incremental hole-drilling technique (IHD), for measuring residual stresses induced by mechanical surface treatments, is proposed here. In practice, it is currently accepted that residual stresses can be accurately determined by IHD if the residual stress level does not exceed about 60% of the material’s yield strength. However, this criterion is not appropriate when IHD is used to measure residual stresses in work-hardened surface layers, since the yield strength of these layers is very difficult to determine. The proposed criterion takes into account the strain-hardening effect and the local yield strength of work-hardened surface layers, using the concept of normalized hardness variation. The criterion was validated experimentally and numerically for shot-peening residual stress measurements.

Analysis of shot-peening and residual stress relaxation in the nickel-based superalloy RR1000

2013 ◽  
Vol 61 (7) ◽  
pp. 2548-2559 ◽  
Author(s):  
B.J. Foss ◽  
S. Gray ◽  
M.C. Hardy ◽  
S. Stekovic ◽  
D.S. McPhail ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Nickel Based Superalloy ◽  
Residual Stress Relaxation
Sign in / Sign up

Export Citation Format

Share Document