X-Ray CT Inspection for Porosities and Its Effect on Fatigue of Die Cast Aluminium Alloy

Kuwazuru, Osamu; Murata, Yozo; Hangai, Yoshihiko; Utsunomiya, Takao; Kitahara, Soichiro; Yoshikawa, Nobuhiro

doi:10.1299/jmmp.2.1220

Cited by 36 publications

(17 citation statements)

References 25 publications

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“…The parameters are determined through fatigue testing of the smooth specimens under uniaxial fatigue loading with different stress ratios. The fatigue test data for ADC12 cast aluminium alloy is taken from the literature [14]. The calculated material parameters in the fatigue damage model are listed in Table 4.…”

Section: Determination Of Materials Parameters For Damage Analysismentioning

confidence: 99%

Continuum damage mechanics based approach to the fatigue life prediction of cast aluminium alloy with considering the effect of porosity

Wang

Meng

2018

MATEC Web Conf.

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Abstract.A damage mechanics based approach is applied for the study of fatigue behaviour of high pressure die cast ADC12 aluminium alloy. A damage coupled elastoplastic constitutive model is presented according to the concept of effective stress and the hypothesis of strain equivalence. An elastic fatigue damage model taking into account the pore-induced stress concentration is developed to investigate fatigue damage evolution of the specimens subjected to cyclic loading. The predicted lives for the specimens with different sizes of pores are consistent with the experimental data. The pore-induced fatigue damage and the variation of fatigue life along with the size of pores are also investigated.

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Section: Determination Of Materials Parameters For Damage Analysismentioning

confidence: 99%

Continuum damage mechanics based approach to the fatigue life prediction of cast aluminium alloy with considering the effect of porosity

Wang

Meng

2018

MATEC Web Conf.

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“…Here, we focus on their effects on the fatigue behavior on the basis of the results of fatigue tests. In our previous study, 8) we conducted fatigue tests on ADC12 aluminum alloy die castings containing relatively large pores. From the X-ray CT inspection, the pore distribution was found to vary widely from specimen by specimen in spite of the same die-casting conditions.…”

Section: Csp-induced Fatigue Life Reductionmentioning

confidence: 99%

“…Revisiting this example, the effect of a CSP on the fatigue behavior is discussed in detail below. Figure 9 shows the three-dimensional pore configurations of rectangular-sectioned specimens used in the previous study 8) before and after a fatigue test under a nominal stress amplitude of a ¼ 80 MPa. The pore configurations were extracted from the X-ray CT images as an isosurface with an appropriate threshold intensity for each specimen.…”

Section: Csp-induced Fatigue Life Reductionmentioning

confidence: 99%

“…[2][3][4][5] In our previous studies, we conducted a microfocus X-ray computed tomography (X-ray CT) observation of ADC12 aluminum alloy die castings containing various types of pores. 6,7) We have also investigated the effect of the pores on the fatigue strength of die castings 8,9) by X-ray CT inspection of the specimens before and after a fatigue test, and found that the fatigue strength depends not only on the quantity and size but also on the geometrical shape of pores. Figure 1 shows an example of an X-ray CT image obtained by scanning an ill-conditioned aluminum alloy die casting that includes numerous gas pores.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 1 shows an example of an X-ray CT image obtained by scanning an ill-conditioned aluminum alloy die casting that includes numerous gas pores. 8) The bright area indicates the aluminum alloy matrix and the dark areas indicate the pores. There were also unclear gray areas, as indicated by a white circle, for which it was difficult to determine whether they were part of the aluminum alloy matrix or pores.…”

Section: Introductionmentioning

confidence: 99%

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Clustered Shrinkage Pores in Ill-Conditioned Aluminum Alloy Die Castings

et al. 2010

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The geometric features of clustered shrinkage pores (CSP) in ill-conditioned aluminum alloy die castings were revealed and their effect on the fatigue strength was discussed. To obtain the geometric features of CSP, an observation using a commercial microfocus X-ray computed tomography (X-ray CT) system was carried out and the position and size of CSP were confirmed. However, the detailed geometry of the CSP could not be clearly observed by X-ray CT, because each pore in the CSP was too small to observe owing to the insufficient resolution of the CT image. We developed a serial sectioning system with a polishing machine and an optical microscope. Observation using the serial sectioning system clearly showed that a CSP consists of many interconnected small pores, which formed an extremely complicated shape. The CSP was thought to grow from relatively large gas pores, which connect to small pores and consequently generate a cavity with a huge volume and a complicated geometry. The complex geometry of CSP resulted in the concentration of stress around CSP, and significantly undermines mechanical properties such as tensile strength and fatigue strength.

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Cold flow defects in zinc die casting: prevention criteria using simulation and experimental investigations

Armillotta

Fasoli²,

Guarinoni

2015

Int J Adv Manuf Technol

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High-pressure die casting of zinc alloys is increasingly used in the manufacturing of parts with high aesthetic value. These parts must comply with strict requirements on surface quality, which are generally overlooked in traditional mechanical applications. Cold flow defects, which are a primary concern for surface quality, originate from several different causes that have not yet been fully understood. This report investigates the factors that influence cold flow defects and the choices that can lead to an improvement in surface quality. The research method is based on a case study performed at a die casting company. First, an existing process has been analyzed using simulation to explain the causes of cold flow defects observed in production samples. The temperature at the end of the cavity fill has emerged as a key index for the occurrence of defects, which can be controlled by three primary process parameters: injection velocity, temperature of the cooling medium, and lubricant spraying time. These same factors are then assessed using experimental tests on an existing die, where the number of defects in the selected regions of the casting has been evaluated by image processing. The results suggest that the surface quality can be particularly improved by increasing the flow rate of the molten metal through the gates and avoiding excessive flow turbulence in the wide cavity sections. Consequently, the increase in the gate area has been identified as a specific criterion for the die design. These findings have been validated in the redesign of the die and the selection of the process parameters, which have resulted in a significant reduction in the surface defects.

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X-Ray CT Inspection for Porosities and Its Effect on Fatigue of Die Cast Aluminium Alloy

Cited by 36 publications

References 25 publications

Continuum damage mechanics based approach to the fatigue life prediction of cast aluminium alloy with considering the effect of porosity

Continuum damage mechanics based approach to the fatigue life prediction of cast aluminium alloy with considering the effect of porosity

Clustered Shrinkage Pores in Ill-Conditioned Aluminum Alloy Die Castings

Cold flow defects in zinc die casting: prevention criteria using simulation and experimental investigations

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