Effect of Shot Peening on Fatigue Properties of Zr-based Amorphous Matrix Composites

2011 ◽  
Vol 1300 ◽  
Author(s):  
Changwoo Jeon ◽  
Choongnyun Paul Kim ◽  
Sunghak Lee
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Amorphous Matrix ◽  
Fatigue Cracks ◽  
Microstructural Analysis ◽  
Fatigue Properties ◽  
Composite Surface ◽  
Cast Composite

AbstractEffects of shot peening on fatigue properties of Zr-based amorphous matrix composite containing ductile crystalline particles were investigated, and fatigue processes were analyzed and compared with those of an as-cast composite. The microstructural analysis results of the shot-peened composite surface indicated that the deformation and surface flexion were observed as the shot-peening time or pressure increased. The compressive residual stress formed on the shot-peened surface was about the half of the ultimate tensile strength, and was not varied much with shot-peening time or pressure. The fatigue limit and fatigue ratio of the shot-peened composite were considerably higher than those of the as-cast composite. This was because the compressive residual stress formed by the shot peening induced the initiation of fatigue cracks at the specimen interior, instead of the specimen surface, thereby leading to the enhanced fatigue limit and fatigue life.

Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

2011 ◽  
Vol 295-297 ◽  
pp. 2227-2230
Author(s):  
Cong Ling Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Work Hardening ◽  
Compressive Residual Stress ◽  
Strain Ratio ◽  
Fatigue Tests ◽  
The Other ◽  
Fatigue Properties ◽  
Torsional Fatigue ◽  
Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

Numerical Study on Strengthening Effect of Laser Shot Peening for Wrought Magnesium Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 2234-2237 ◽  
Author(s):  
Su Qin Jiang ◽  
Hong Guang Xu
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Numerical Study ◽  
Back Analysis ◽  
Laser Shot ◽  
Fatigue Properties ◽  
Strengthening Effect ◽  
Fea Model

Based on finite element method, the FEA model used for analyzing fatigue properties of sample treated by laser shot peening (LSP) was established. In order to research the influence of material intensity on LSP effect, two kinds of wrought magnesium alloys AZ31B and ZK60 with different intensity were chosen as object, the compressive residual stress and fatigue life after LSP were analyzed. After spring back analysis the elastic strain is released in material inner, the value of compressive residual stress was reduced; after LSP with 3 times, the fatigue life gains of AZ31B and ZK60 were 105% and 163%, respectively. The results show that strengthening effect of high intensity material treated by LSP is better than that of low intensity material.

scholarly journals Fatigue Limit of Custom 465 with Surface Strengthening Treatment

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 238 ◽  
Author(s):  
Gang An ◽  
Ren-jing Liu ◽  
Guang-qiang Yin
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Limit ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Subsurface Layer ◽  
Micro Hardness ◽  
Surface Residual Stress ◽  
Surface Strengthening ◽  
The Relationship

In order to study the effect of nitriding or shot peening on the surface modification and fatigue properties of martensitic stainless-steel Custom 465, the residual stress and micro-hardness of the strengthened layer are determined by X-ray and micro-hardness tester, respectively. The up-and-down method is used to measure the rotational bending fatigue strength at 1 × 107 cycles, and the fatigue fracture characteristic is observed by scanning electron microscopy. The relationship between surface residual stress and internal fatigue limit of surface strengthening treatment is discussed. Results show that nitriding or shot peening surface strengthening layer forms a certain depth of compressive residual stress, where in the surface compressive residual stress of the nitrided specimens is greater than the shot peened specimens. The micro-hardness of the nitrided or shot peened surface strengthening layer is significantly improved, where in the surface micro-hardness of nitriding specimens are higher than shot peening specimens. The nitriding or shot peening surface strengthening can significantly improve the fatigue limit of Custom 465, wherein the fatigue limits of nitrided and shot peened surface strengthened specimens are 50.09% and 50.66% higher than that of the un-surface strengthened specimens, respectively. That is, the effect of the two strengthening methods on fatigue limit is not very different. The fracture characteristics show that the fatigue crack of the un-surface strengthened specimens originates from the surface, while the fatigue crack of surface strengthened specimens originates from the subsurface layer under the strengthened layer. The relationship between the internal fatigue limit and the surface residual stress of the surface strengthened specimen can be used as a method for predicting the fatigue limit of the surface strengthened specimens.

scholarly journals Effects of shot peening and artificial surface defects on fatigue properties of 50CrV4 steel

2021 ◽  
Vol 112 (9-10) ◽  
pp. 2961-2970
Author(s):  
Nursen Saklakoglu ◽  
Amir Bolouri ◽  
Simge Gencalp Irizalp ◽  
Fatih Baris ◽  
Ali Elmas
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Surface Defects ◽  
Fatigue Properties ◽  
Root Radius ◽  
Defect Depth ◽  
Near Surface ◽  
Artificial Surface

AbstractShot peening processes are commonly used for improving the fatigue properties of steels. Shot peening introduces a compressive residual stress field in the near surface of steel, which can reduce or stop the growth of fatigue cracks and improve fatigue properties. This study experimentally investigated the effect of shot peening on the fatigue properties of 50CrV4 steel alloys with different artificial surface defects. Drilling tools were used to introduce different artificial defects with root radii of 0.585 mm and 0.895 mm on the surface of unpeened samples. The shot peening was applied to the drilled and undrilled samples. Scanning electron microscopy (SEM) observations, micro-hardness and X-ray diffraction residual stress measurements were conducted to analyse the characteristics of the shot-peened and unpeened samples. The results show that the shot peening leads to the transformation of the retained austenite to martensite in the near-surface microstructure. The hardness rates of the surface and near surface both increase by 8% after the shot peening. The peened samples exhibit compressive residual stresses with a high degree of isotropy in the near surface. The fatigue properties of samples were experimentally evaluated by conducting 3-point bending tests. The results indicate that the shot peening improves the fatigue life of drilled and undrilled samples. For the defects with the root radius of 0.895 mm, the shot peening leads to a 500% improvement in the fatigue life compared to unpeened samples regardless of defect depth. For the defects with the root radius of 0.585 mm, the improvement in fatigue life is 40% for the defect depth of 0.2 mm compared to unpeened samples. The improvement increases to 60% and 200% by increasing the defect depths to 0.4 mm and 0.6 mm. The fatigue properties are linked to the changes in the features of defects mainly caused by the deformation hardening and compressive residual stress after shot peening.

Influence of Shot Peening on Fatigue Properties in Ultra-High Strength Steels

2005 ◽  
Vol 490-491 ◽  
pp. 448-453 ◽  
Author(s):  
Yu Kui Gao ◽  
Xue Ren Wu ◽  
Feng Lu ◽  
Mei Yao ◽  
Qingxian Yan
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Limit ◽  
Surface Integrity ◽  
Shot Peening ◽  
Fatigue Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Properties ◽  
Ultra High Strength Steels

The characteristics of compressive residual stress fields induced by shot peening in 40CrNi2Si2MoVA, 16Co14Ni10Cr2Mo, 30CrMnSiNi2A and 0Cr13Ni8Mo2Al ultra-high strength steels, which are used widely in aeronautical industry were investigated, and the change of surface integrity including surface residual stress, surface roughness as well as its effects on fatigue properties were investigated. The results show that the fatigue limits of ultra-high strength steels can be increased by shot peening because the surface integrity can be ameliorated by shot peening, and that for a given steel there is a appropriate peening intensity under which the fatigue property of this steel is optimum. Finally, a judgement for the optimization condition of shot peening process is proposed based on a theory of micro-meso processes of fatigue crack initiation and experimental results. The technique should be considered to be optimum, if the fatigue crack source of shot peened specimen has been moved to the internal matrix metal region beneath the hardened layer; and its apparent fatigue limit has been improved and got to a value, which is near to that predicted according to the concept of surface/internal fatigue limit.

scholarly journals Effect of surface compressive residual stress introduced by surface treatment on fatigue properties of metallic material

2018 ◽  
Vol 165 ◽  
pp. 18006
Author(s):  
Jinta Arakawa ◽  
Tatsuya Hanaki ◽  
Yoshiichirou Hayashi ◽  
Hiroyuki Akebono ◽  
Atsushi Sugeta
Keyword(s):  
Residual Stress ◽  
Surface Treatment ◽  
Fatigue Limit ◽  
Compressive Residual Stress ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Mean Stress ◽  
Metallic Material ◽  
Effect Of Surface

This study considers shakedown in evaluating the fatigue limit of metals with compressive residual stress at the surface. We begin by applying tension-compression fatigue tests to ASTM CA6NM under conditions of controlled load and displacement to obtain fatigue limit diagram in compressive mean stress. The results imply that shakedown occurs under the condition of controlled displacement, therefore, shakedown should be considered when evaluating the fatigue limit of metals with compressive residual stress at the surface.

scholarly journals Contribution to Improvement of Fatigue Properties of Zr-4 Alloy: Gradient Nanostructured Surface Layer versus Compressive Residual Stress

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3125
Author(s):  
Donghui Geng ◽  
Qiaoyan Sun ◽  
Chao Xin ◽  
Lin Xiao
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Fatigue Strength ◽  
Compressive Residual Stress ◽  
Fatigue Cracks ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Layer Versus ◽  
Mechanical Grinding ◽  
The Individual

The gradient nanostructured (GNS) layer forms beneath the surface of Zr-4 samples by the surface mechanical grinding treatment (SMGT) process, which increases the fatigue strength apparently due to the synergistic effect of the gradient nanostructured layer and compressive residual stress. The SMGTed Zr-4 samples are subjected to annealing to remove residual stress (A-SMGT) and the individual effect of the GNS layer and compressive residual stress can be clarified. The results show that the gradient nanostructure in the surface is stable after annealing at 400 °C for 2 h but residual stress is apparently removed. Both SMGTed and A-SMGTed Zr-4 samples exhibit higher fatigue strength than that of coarse-grained (CG) Zr-4 alloy. The fatigue fracture of Zr-4 alloy indicates that the hard GNS surface layer hinders fatigue cracks from approaching the surface and leads to a lower fatigue striation space than that of CG Zr-4 samples. The offset fatigue strength of 106 cycles is taken for SMRT-ed, A-SMRT-ed, and CG Zr-4 samples and the results indicate clearly that the GNS surface layer is a key factor for the improvement of fatigue strength of the Zr-4 alloy with surface mechanical grinding treatment.

The Effect of Compressive Residual Stress on the Fatigue Characteristics of Al6061

2006 ◽  
Vol 324-325 ◽  
pp. 1181-1184
Author(s):  
Won Jo Park ◽  
Sun Chul Huh ◽  
Kang Young Lee ◽  
Sung Ho Park ◽  
Hwa Sik Hwang
Keyword(s):  
Residual Stress ◽  
Fatigue Test ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
High Stress ◽  
High Hardness ◽  
Fatigue Properties ◽  
Test Results ◽  
Surface Conditions ◽  
Fatigue Characteristics

Recently, the steel parts used at the aerospace and automobile industries are required to be used high stress more than ever before in need of the weight down. Therefore, used material steel have to be a high stress, which is an indispensable condition in this field. At the consideration of parts design, high hardness of the lightweight parts has an benefit of saving fuel and material. In this study, the surface conditions are measured to know the influence on fatigue properties by shot peening. In this study, the optimum shot peening condition is investigated. Fatigue test was accomplished to investigate the effects of compressive residual stress by shot peening on fatigue characteristics. Test results show the fatigue characteristics were increased by optimum peening condition. But the fatigue characteristics were decreased by under peening or over peening condition.

Characterization of nanocrystalline surface layer induced by shot peening and effect on their fatigue strength.

2004 ◽  
Vol 843 ◽  
Author(s):  
Hideo Mano ◽  
Kondo Satoru ◽  
Akihito Matsumuro ◽  
Toru Imura
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Fatigue Strength ◽  
Vickers Hardness ◽  
Shot Peening ◽  
White Layer ◽  
The Other ◽  
Fatigue Properties ◽  
Nanocrystalline Layer

ABSTRACTThe shot peening process is known to produce a hard layer, known as the white layer” on the surface of coil springs. However, little is known about the fatigue properties of this white-layer.In this study, coil springs with a white-layer were manufactured. The surface of these springs was then examined using micro Vickers hardness, FE-SEM etc. to test fatigue strength of the springs.From the results obtained, a microstructure of the white-layer with grain size of 50–100 nm was observed, with a Vickers hardness rating of 8–10 GPa.Tow category springs were manufactured utilizing a double-peening process. These springs had the same residual stress destruction and surface roughness. Only one difference was observed: one spring had a nanocrystalline layer on the surface, while the other did not. The results of the fatigue test realized an increase in the fatigue life of the nanocrystalline surface layer by 9%.

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