The effect of quenching and defects size on the HCF behaviour of Boron steel

Pessard, Etienne; Abrivard, Benjamin; Morel, Franck; Abroug, Foued; Delhaye, Philippe

doi:10.1016/j.ijfatigue.2014.06.002

Cited by 18 publications

(11 citation statements)

References 27 publications

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“…In order to take into account the addition of copper in the chemical compositions (for alloy A), it is proposed to make the Dang-Van parameter b a function of the micro-hardness of the alpha phase dendrites, b ¼ f ðHvÞ. This approach has been used by Pessard et al [30] for a Boron steel, in which b ¼ f ðHvÞ was chosen to be a linear function. Regarding the change in crack initiation mechanism observed when the maximum hydrostatic stress is increased, it is proposed that instead of using a unique coefficient a DV to reflect the effect of the maximum hydrostatic stress as per the classical Dang-Van criterion (see Eq.…”

Section: The Dang Van and Modified Lefm Criteria Combination -Taking mentioning

confidence: 99%

Simulation of the Kitagawa-Takahashi diagram using a probabilistic approach for cast Al-Si alloys under different multiaxial loads

Morel

Bellett

et al. 2016

International Journal of Fatigue

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This article describes a microstructural-based high cycle fatigue strength modelling approach applied to different cast Al-Si alloys used in an automotive context. Thank to different casting processes (gravity die casting and lost foam casting), associated with several heat treatment (T7 and Hot Isostatic Pressing-HIP), three alloys with very different microstructures have been obtained. In a vast experimental campaign undertaken to investigate the fatigue damage mechanisms governing these alloys under different multiaxial loading conditions, it was shown that the principal crack initiation mechanisms for the porosity-free alloy are either the formation of persistent slip bands (PSB) or the rupture and/or debonding of eutectic particles. For the porosity-containing alloys, the fatigue damage is always controlled by crack growth from pores. In order to take into account these fatigue damage mechanisms, a probabilistic model using a combination of the Dang Van and a modified LEFM criteria is proposed. The modified LEFM criterion is able to take into account the influence of the grain size on the threshold of the stress intensity factor. It is shown that for the porosity-free alloy, the predictions are good for combined tension-torsion loads with R ¼ À1. However, because the crack initiation mechanisms are not the same depending on the hydrostatic stress, the predictions are non-conservative for the uniaxial and equibiaxial tension loads with R ¼ 0:1. For the porosity-containing alloys, the predictions are very good for the uniaxial, combined tension-torsion and equibiaxial tension loads with both R ¼ À1 and R ¼ 0:1. As observed experimentally, the proposed model can also predict a more pronounced effect of casting porosity for the uniaxial and combined tension-torsion loads, when compared to pure torsion loads.

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Section: The Dang Van and Modified Lefm Criteria Combination -Taking mentioning

confidence: 99%

Simulation of the Kitagawa-Takahashi diagram using a probabilistic approach for cast Al-Si alloys under different multiaxial loads

Morel

Bellett

et al. 2016

International Journal of Fatigue

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“…In our case, the samples are the fatigue specimens, the reference area S 0 is therefore the surface distribution, but the depth does not. The parameters for the K t distribution can be calculated with equation (6), and the maximum K t on a larger sample can be predicted with equation (9). The reference surface being one specimen, the return period T can be considered to be the total number of specimens in the larger sample.…”

Section: Predicting the Maximum Defect Size On A Larger Samplementioning

confidence: 99%

“…A classic example is Murakami's work [6,7]. More recently, studies have been performed on steel [8,9,10], on cast iron [11,12,13], on cast aluminium alloys [14,15,16] and cast titanium alloys [17]. Most investigations on defects are performed on homogeneous materials, without residual stresses.…”

Section: Introductionmentioning

confidence: 99%

A non-local approach to model the combined effects of forging defects and shot-peening on the fatigue strength of a pearlitic steel

Gerin

Pessard

Morel

et al. 2018

Theoretical and Applied Fracture Mechanics

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This study focuses on the influence on fatigue behaviour of the surface integrity of a steel connecting rod. The component is hot-forged and shot-blasted, producing a complex surface state with large surface defects and high residual stresses. In a prior study, the surface was thoroughly characterized and fatigue tests were performed. Several different surface states were analysed in order to quantify the influence of the various surface aspects. These tests showed that the forging defects and the residual stresses are the most influential aspects of the surface. The goal of this paper is to develop an approach capable of taking into account the influence of both these aspects on fatigue behaviour. Two methods were developed. First, using surface scans of the fatigue specimens, the forging defects were fitted with ellipsoids so as to determine their size and shape. This allows to easily compare the numerous defects and test various criteria in order to identify the critical defect of each specimen. The second method used was the finite element simulation of the defects based on real topography scans. Using a non-local approach based on the theory of critical distances, the simulations were used to accurately predict the influence of the defects' geometry. The residual stress profiles were integrated in the simulations using Dang Van's criterion. The predictions are accurate and show the importance of taking into account the real defect geometry when estimating the fatigue strength.

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“…In metallic alloys, defects can originate from material elaboration [1], manufacturing processes [2,3] or foreign-object impacts [4]. These defects have either 4 a geometrical (e.g.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the impact of geometrical defects on the high cycle fatigue behavior of polycrystalline aluminium with different grain sizes

Bracquart

Mareau

Saintier

et al. 2018

International Journal of Fatigue

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Geometrical defects are known to have a detrimental influence on the high cycle fatigue resistance of metallic alloys, smaller defects being less harmful. In this experimental work, the influence of the defect size on the high cycle fatigue behavior of polycrystalline aluminium with different grain sizes is investigated, to better understand the role of internal length scales. Firstly, different thermomechanical treatments are applied to obtain aluminium samples with either small (100 µm) or large (1000 µm) grains. The samples are used for preparing fatigue specimens, with either small (100 µm) or large (1000 µm) hemispherical defects. Fully reversed stress-controlled fatigue tests are then carried out.

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The effect of quenching and defects size on the HCF behaviour of Boron steel

Cited by 18 publications

References 27 publications

Simulation of the Kitagawa-Takahashi diagram using a probabilistic approach for cast Al-Si alloys under different multiaxial loads

Simulation of the Kitagawa-Takahashi diagram using a probabilistic approach for cast Al-Si alloys under different multiaxial loads

A non-local approach to model the combined effects of forging defects and shot-peening on the fatigue strength of a pearlitic steel

Experimental study of the impact of geometrical defects on the high cycle fatigue behavior of polycrystalline aluminium with different grain sizes

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