Application of X-ray microtomography to study the influence of the casting microstructure upon the tensile behaviour of an Al–Si alloy

Limodin, Nathalie; Bartali, Ahmed El; Wang, Long; Lachambre, Joël; Buffière, Jean‐Yves; Charkaluk, Éric

doi:10.1016/j.nimb.2013.07.034

Cited by 39 publications

(37 citation statements)

References 14 publications

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“…Such unmelted zones are observed in the bulk or in sub-surface areas. As the position of the defects respectively to the surface is an influencing parameter on the crack initiation time, as shown in the case of shrinkage in casting alloys [4,5], this has an impact on the criticality and the lifetimes. In the case of unmelted zones, one can observe in Figure 3 that the fatigue properties are qualitatively slightly better for the specimens built in the XY direction.…”

Section: Discussion and Comparison With Casting Processesmentioning

confidence: 99%

“…In fact, in the case of casting alloys, it has been shown that a simple 2D analysis (size, morphology) from data extracted from surface images of such complex 3D defects is generally not sufficient to understand and quantify their impact on crack initiation mechanisms and on lifetime, even if some statistical corrections are possible [11]. Therefore, a systematic 3D quantitative analysis of the specimens microstructure by CT-tomography (as conducted in [6]) could be a direct perspective of this work, associated to in-situ fatigue tests as in [4,5].…”

Section: Discussion and Comparison With Casting Processesmentioning

confidence: 99%

“…At the microstructure scale, it is shown that surface defects and unmelted zones seem to be the dominant features. As this type of defect is close to casting ones, these fatigue crack initiation processes are then compared and discussed with the ones identified in specimens obtained from casting processes [4][5][6]. In these previous studies, the main interest was the possibility to observe, qualify and quantify on in-situ tests, the three dimensional mechanisms responsible of the crack initiation and the microcrack growth.…”

Section: Introductionmentioning

confidence: 88%

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Fatigue of Additive Manufacturing Specimens: A Comparison with Casting Processes

Charkaluk

Chastand

2018

The 18th International Conference on Experimental Mechanics

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Abstract:In this paper, the specificity and/or the common features of materials coming from such new additive manufacturing processes will be compared to more classical one, like casting process. Fatigue properties of Ti-6Al-4V specimens built by EBM and SLM are first compared depending on several process parameters. Then, at the microstructure scale, it is shown that surface defects and unmelted zones seem to be the dominant features. It will be shown that similarities can then be drawn with casting processes where shrinkage and pores are also associated to damage mechanisms.

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Section: Discussion and Comparison With Casting Processesmentioning

confidence: 99%

Section: Discussion and Comparison With Casting Processesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

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Fatigue of Additive Manufacturing Specimens: A Comparison with Casting Processes

Charkaluk

Chastand

2018

The 18th International Conference on Experimental Mechanics

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“…The most commonly used methods to detect internal casting defects are X-rays, the tightness test, ultrasonic testing or the eddy current technique [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Porosity Characterization of Aluminium Castings by Using Particular Non-destructive Techniques

Wilczek¹,

Długosz

Hebda

2015

J Nondestruct Eval

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In this paper is presented an analysis of a comparison of particular non-destructive techniques: radiographic, ultrasonic, eddy current and pulsed infrared thermography to detect flaws in pressure die casting. Furthermore, a new way of the image segmentation method for porosity detection in aluminium pressure die casting using results from X-ray analysis and public domain software is proposed. The results of the research allowed verifying the possibility of using the aforesaid methods in controlled technological parameters of the casting process, and thus permitted confirming the quality of the manufactured castings. It was found that the radiographic method was the most preferred means for evaluating the quality of products and for optimizing the technological process for aluminium pressure casting. It permits a fast analysis of casting defects in the finished products, and when combined with the computer image analysis (the porosity segmentation algorithm as described in the article) it allows drawing conclusions regarding their causes (e.g. based on the size and shape analysis of the pores detected). The ultrasonic testing method can also be used to evaluate the quality of the casting (to detect it but without the possibility of interpreting the size or source of origin). The results obtained via this method allow for proper control of die casting parameters. B Marek Hebda

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“…• C for 200 h. A full 3D characterization of the microstructure through X-ray tomography [2] is performed in order to measure the size and shape distribution of pores in a Representative Elementary Volume while 2D analyses are also carried out on samples cut from the same cylinder a Corresponding author: fabien.szmytka@mpsa.com This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.…”

Section: Introductionmentioning

confidence: 99%

Probabilistic thermal-mechanical fatigue criterion for lost foam casting aluminium alloys based on 2D/3D porosities distribution

Szmytka

Limodin

Wang

et al. 2014

MATEC Web of Conferences

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Abstract.A thermal-mechanical fatigue criterion is proposed to assess the lifetime of aluminium alloys produced by a lost foam casting process. It is based on the observed size distribution of pores sizes which are considered as critical zones for cracks initiation and gives reliable results when both pores sizes are identified from X-ray tomography and mean stresses are taken into account. Lifetime probabilities are finally successfully compared with experimental results.Nowadays, car engines tend to be exposed to very high temperature and pressure during their nominal use, to improve their performance and to reduce their environmental impact. This trend requires the use of new materials or new processes for avoiding thermal-mechanical fatigue (TMF) damage in cylinder heads that are subjected to increasing temperatures and stresses. Lost Foam Casting (LFC) is a process that enables to easily adapt the geometry of cast structures against TMF with a reduced cost. It is now widely used in the automotive industry to produce cylinder heads out of aluminium alloys. However, its main drawback lies in the presence of more numerous pores and intermetallics, defects that can help to initiate TMF cracks. Pores are here taken as the defect population on which TMF cracks initiate.The studied materials are two aluminum-silicon alloys used in the automotive industry: A356 with T7 heat treatment and A319 without heat treatment. This study focuses essentially on the materials obtained by LFC process which has a great impact on the microstructure of the materials as it was already illustrated in [1]. Fatigue data have been obtained on over-aged materials to ensure stable mechanical behaviour. The over-aging has been determined by the stabilisation both in terms of mechanical properties and of microstructure of the material which corresponds here to the heating of materials at 250• C for 200 h. A full 3D characterization of the microstructure through X-ray tomography [2] is performed in order to measure the size and shape distribution of pores in a Representative Elementary Volume while 2D analyses are also carried out on samples cut from the same cylinder a Corresponding

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Application of X-ray microtomography to study the influence of the casting microstructure upon the tensile behaviour of an Al–Si alloy

Cited by 39 publications

References 14 publications

Fatigue of Additive Manufacturing Specimens: A Comparison with Casting Processes

Fatigue of Additive Manufacturing Specimens: A Comparison with Casting Processes

Porosity Characterization of Aluminium Castings by Using Particular Non-destructive Techniques

Probabilistic thermal-mechanical fatigue criterion for lost foam casting aluminium alloys based on 2D/3D porosities distribution

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