Clustered shrinkage pores in ill-conditioned aluminum alloy die castings

Yoshihiko Hangai, Osamu Kuwazuru, Takayuki Yano, Takao Utsunomiya, Yozo Murata, Soichiro Kitahara, Sujit Bidhar, Nobuhiro Yoshikawa

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1574-1580
Number of pages7
JournalMaterials Transactions
Volume51
Issue number9
DOIs
Publication statusPublished - 2010 Sep

Fingerprint

Die castings
shrinkage
aluminum alloys
Aluminum alloys
porosity
Tomography
Geometry
Polishing machines
X rays
geometry
tomography
Microscopes
Tensile strength
Gases
optical microscopes
polishing
tensile strength

Keywords

  • Aluminum alloy
  • Casting defect
  • Die casting
  • Fatigue
  • Serial sectioning
  • Shrinkage porosity
  • X-ray computed tomography

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

Cite this

Hangai, Y., Kuwazuru, O., Yano, T., Utsunomiya, T., Murata, Y., Kitahara, S., ... Yoshikawa, N. (2010). Clustered shrinkage pores in ill-conditioned aluminum alloy die castings. Materials Transactions, 51(9), 1574-1580. https://doi.org/10.2320/matertrans.MAW201032

Clustered shrinkage pores in ill-conditioned aluminum alloy die castings. / Hangai, Yoshihiko; Kuwazuru, Osamu; Yano, Takayuki; Utsunomiya, Takao; Murata, Yozo; Kitahara, Soichiro; Bidhar, Sujit; Yoshikawa, Nobuhiro.

In: Materials Transactions, Vol. 51, No. 9, 09.2010, p. 1574-1580.

Research output: Contribution to journalArticle

Hangai, Y, Kuwazuru, O, Yano, T, Utsunomiya, T, Murata, Y, Kitahara, S, Bidhar, S & Yoshikawa, N 2010, 'Clustered shrinkage pores in ill-conditioned aluminum alloy die castings', Materials Transactions, vol. 51, no. 9, pp. 1574-1580. https://doi.org/10.2320/matertrans.MAW201032
Hangai, Yoshihiko ; Kuwazuru, Osamu ; Yano, Takayuki ; Utsunomiya, Takao ; Murata, Yozo ; Kitahara, Soichiro ; Bidhar, Sujit ; Yoshikawa, Nobuhiro. / Clustered shrinkage pores in ill-conditioned aluminum alloy die castings. In: Materials Transactions. 2010 ; Vol. 51, No. 9. pp. 1574-1580.
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