scholarly journals Improvement in Fatigue Performance of Aluminium Alloy Welded Joints by Laser Shock Peening in a Dynamic Strain Aging Temperature Regime

Materials ◽  
2016 ◽  
Vol 9 (10) ◽  
pp. 799 ◽  
Author(s):  
Chun Su ◽  
Jianzhong Zhou ◽  
Xiankai Meng ◽  
Shu Huang
Keyword(s):  
Aluminium Alloy ◽  
Dynamic Strain Aging ◽  
Temperature Regime ◽  
Welded Joints ◽  
Aging Temperature ◽  
Strain Aging ◽  
Laser Shock Peening ◽  
Dynamic Strain ◽  
Laser Shock ◽  
Shock Peening

Alternative Mechanical Surface Treatments for Fatigue Strength Enhancement

2005 ◽  
Vol 490-491 ◽  
pp. 328-333 ◽  
Author(s):  
I. Altenberger
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Strain Aging ◽  
Fatigue Behavior ◽  
Laser Shock Peening ◽  
Dynamic Strain ◽  
Laser Shock ◽  
Deep Rolling ◽  
Shock Peening ◽  
Mechanical Surface

In this paper, The effects of laser-shock peening and high temperature deep rolling on nearsurface microstructures, residual stress states and fatigue behavior of various metallic materials are investigated and discussed. Similar to warm peening (shot peening at elevated temperatures), high temperature deep rolling may induce several favourable effects, especially in ferritic steels, where dynamic strain aging by carbon atoms can be exploited as a major strengthening mechanism. But also in materials without ‚classical‘ strain aging high temperature deep rolling is effective in improving the fatigue behaviour by inducing favourable, e.g. precipitation-hardened, nearsurface microstructures. As a consequence, these modified near-surface microstructures directly alter the thermal and mechanical relaxation behaviour of residual stresses. Laser-shock peening is already used in the aircraft industry (as a mechanical surface treatment for fan-blades) and owes its benefial effects to deep layers of compressive residual stress and work hardening and a relatively smooth surface roughness. Characteristic examples of microstructures and residual stress profiles as generated by laser-shock peening are presented. Moreover, the impact on the fatigue behavior of steels and a titanium alloy is outlined and discussed.

Fatigue Performance Improvement by Dynamic Strain Aging and Dynamic Precipitation in Warm Laser Shock Peening of AISI 4140 Steel

2010 ◽  
Author(s):  
Chang Ye ◽  
Gary J. Cheng
Keyword(s):  
Strain Aging ◽  
Laser Shock Peening ◽  
Dynamic Strain ◽  
Laser Shock ◽  
Dynamic Precipitation ◽  
Surface Strength ◽  
Aisi 4140 Steel ◽  
Aisi 4140 ◽  
Life Improvement ◽  
Shock Peening

Warm laser shock peening (WLSP) integrates the advantages of laser shock peening and thermal-mechanical treatment (TMT) to improve material fatigue performance. Compared to traditional laser shock peening (LSP), warm laser shock peening, i.e. LSP at elevated temperature, leads to better performance in many aspects. WLSP can induce nanoscale precipitations by dynamic precipitation and high density dislocation by dynamic strain aging (DSA), resulting in higher surface strength, which is beneficial for fatigue life improvement. Due to pinning of dislocation structure by nanoscale precipitates, and the pinning of dislocation structure by Cottrell atmosphere, or the DSA effect, stability of the dislocation arrangement is significantly increased and the residual stress stability improved. In this study, AISI 4140 steel is used to evaluate WLSP process. It is concluded that the higher residual stress stability and higher surface strength caused by dynamic precipitation and DSA in WLSP leads to fatigue life improvement.

Experimental and Numerical Analysis of the Distribution of Residual Stresses Induced by Laser Shock Peening in a 2050-T8 Aluminium Alloy

2011 ◽  
Vol 681 ◽  
pp. 296-302 ◽  
Author(s):  
Neila Hfaiedh ◽  
P. Peyre ◽  
I. Popa ◽  
Vincent Vignal ◽  
Wilfrid Seiler ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Residual Stress Distribution ◽  
Laser Shock Peening ◽  
Treatment Technique ◽  
Laser Shock ◽  
X Ray Diffraction ◽  
Shock Peening

Laser shock peening (LSP) is an innovative surface treatment technique successfully applied to improving fatigue performance of metallic material. The specific characteristic of (LSP) is the generation of a low work-hardening and a deep compressive residual stresses mechanically produced by a laser-induced shock wave propagating in the material. The aim of this study is to analyse the residual stress distribution induced by laser peening in 2050-T8 aluminium alloy experimentally by the X-ray diffraction technique (method sin2Y) and numerically, by a finite element numerical modelling. A specific focus was put on the residual stress distribution along the surface of the impacted material.

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