Influence of laser peening on microstructure and fatigue lives of Ti–6Al–4V
01 Oct 2014-Transactions of Nonferrous Metals Society of China (Elsevier)-Vol. 24, Iss: 10, pp 3111-3117
TL;DR: In this article, the influence of low energy laser peening on fatigue lives of Ti-6Al-4V was investigated, which resulted in the formation of nanocrystallites on the surface and near surface regions with associated increase in hardness and introduction of compressive residual stress.
About: This article is published in Transactions of Nonferrous Metals Society of China.The article was published on 2014-10-01. It has received 38 citations till now. The article focuses on the topics: Laser peening & Peening.
Citations
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TL;DR: In this article, the microstructure evolution and grain refinement of Ti-6Al-4V alloy after laser shock processing (LSP) are systematically investigated in a Q-switched Nd:YAG laser system operated with a wave-length of 1064nm and 10ns pulse width.
94 citations
TL;DR: In this article, the effects of different frequencies and loads of multi-pass ultrasonic surface rolling (MUSR) on surface layer mechanical properties, microstructure and fretting friction and wear characteristics of HIP (hot isostatic pressing) Ti-6Al-4V alloy were investigated.
81 citations
TL;DR: In this article, a laser peening experiment was conducted to investigate the fatigue life of Ti17 titanium alloy by using Nd:YAG laser system with the pulse-width of 15 ns and max pulse-energy of 7 J.
53 citations
TL;DR: Titanium and its alloys are widely used in aerospace, biomedicine, chemical industries, and other fields due to the excellent properties such as high specific strength, strong corrosion resistance, and...
Abstract: Titanium and its alloys are widely used in aerospace, biomedicine, chemical industries, and other fields due to the excellent properties as high specific strength, strong corrosion resistance, and ...
29 citations
28 citations
References
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TL;DR: In this paper, the authors used a Geiger counter spectrometer to measure the changes in intensity distribution in the spectra of cold worked aluminium and wolfram and found that the line breadths may be attributed to simultaneous small particle size and strain broadening, the latter predominating at the higher Bragg angles.
7,802 citations
TL;DR: The use of the Voigt function for the analysis of the integral breadths of broadened X-ray diffraction line profiles forms the basis of a rapid and powerful single-line method of crystallite size and strain determination which is easy to apply.
Abstract: The use of the Voigt function for the analysis of the integral breadths of broadened X-ray diffraction line profiles forms the basis of a rapid and powerful single-line method of crystallite-size and strain determination which is easy to apply. To avoid graphical methods or interpolation from tables, empirical formulae of high accuracy are used and an estimation of errors is presented, including the influence of line-profile asymmetry. The method is applied to four practical cases of size-strain broadening: (i) cold-worked nickel, (ii) a nitrided steel, (iii) an electrodeposited nickel layer and (iv) a liquid-quenched AlSi alloy.
1,085 citations
15 Jun 1996-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the role of laser shock processing (LSP) on the cyclic properties of A356, Al12Si and 7075 aluminium alloys was evaluated, and major contributors to the fatigue performance improvements were investigated in order to determine the optimum shock conditions.
Abstract: Subjecting target metallic samples to a very short pulse (about 20 ns) of intense (GW cm−2) laser light generates, through a surface plasma, a high-pressure stress wave propagating to the first millimetre in depth, which is commonly called laser shock processing (LSP). The purpose of this work was to evaluate the role of this novel process on the cyclic properties of A356, Al12Si and 7075 aluminium alloys. Major contributors to the fatigue performance improvements were investigated in order to determine the optimum shock conditions. These were mainly compressive residual stress (RS) levels for which a large range of incident shock conditions was performed. We showed that stress levels were very sensitive to the laser fluence and the number of local impacts, and experimental RS measurements were found to be in good agreement with analytical modelling results. In comparison, a conventional shot peening (SP) treatment was found to lead to higher surface hardening and RS levels, but with a very detrimental roughening not observed after LSP. High cycle (107) fatigue tests carried out on laser- processed, shot-peened and untreated notched samples illustrated the efficiency of LSP as a new, promising method to improve the fatigue limits σD of structures, especially in comparison with enhancements displayed by SP (+22% vs. +10%). According to crack detection electric measurements, fatigue performance improvements with LSP mainly occurred during the crack initiation stage.
587 citations
25 Aug 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of DR on the low-cycle fatigue (LCF) and high cycle fatigue (HCF) behavior of a Ti-6Al-4V alloy is examined, with particular emphasis on the thermal and mechanical stability of the residual stress states and the near-surface microstructures.
Abstract: It is well known that mechanical surface treatments, such as deep rolling, shot peening and laser shock peening, can significantly improve the fatigue behavior of highly-stressed metallic components. Deep rolling (DR) is particularly attractive since it is possible to generate, near the surface, deep compressive residual stresses and work hardened layers while retaining a relatively smooth surface finish. In the present investigation, the effect of DR on the low-cycle fatigue (LCF) and high-cycle fatigue (HCF) behavior of a Ti–6Al–4V alloy is examined, with particular emphasis on the thermal and mechanical stability of the residual stress states and the near-surface microstructures. Preliminary results on laser shock peened Ti–6Al–4V are also presented for comparison. Particular emphasis is devoted to the question of whether such surface treatments are effective for improving the fatigue properties at elevated temperatures up to ∼450 °C, i.e. at a homologous temperature of ∼0.4 T/T m (where T m is the melting temperature). Based on cyclic deformation and stress/life ( S / N ) fatigue behavior, together with the X-ray diffraction and in situ transmission electron microscopy (TEM) observations of the microstructure, it was found that deep rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in Ti–6Al–4V at such higher temperatures, despite the almost complete relaxation of the near-surface residual stresses. In the absence of such stresses, it is shown that the near-surface microstructures, which in Ti–6Al–4V consist of a layer of work hardened nanoscale grains, play a critical role in the enhancement of fatigue life by mechanical surface treatment.
466 citations
15 May 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the influence of mechanical surface treatments on magnesium fatigue strength was investigated in relation to the relatively well-studied titanium and aluminum alloys, and the results showed that these changes can have contradictory influences on the fatigue strength.
Abstract: Generally, mechanical surface treatments induce high dislocation densities in near-surface regions. Due to the local plastic deformation, residual stresses are developed and the surface topography is changed. These changes can have contradictory influences on the fatigue strength. Results on the influence of mechanical surface treatments on magnesium are presented in relation to the relatively well-studied titanium and aluminum alloys.
370 citations