Frequency analysis of volumetric porosity in aluminum castings at high and low cooling rates

Fahad A. Al Mufadi; Mohammad A. Irfan

doi:10.3139/120.110727

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Article

Frequency analysis of volumetric porosity in aluminum castings at high and low cooling rates

Fahad A. Al Mufadi and Mohammad A. Irfan

Published/Copyright: April 21, 2015

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From the journal Materials Testing Volume 57 Issue 5

Abstract

Three dimensional porosity analysis was conducted using computed tomography for Al-Si alloy castings. Statistical analysis was performed to compare the porosities of the castings at high and low cooling rates. It was observed that the cooling rates strongly affect the formation of pores for both small and large pores. The incidence of small pores measuring 0.00003 mm³ to 0.0004 mm³ can be up to six times higher in castings formed at low cooling rates. For large pores measuring 300 μm to 360 μm, it was observed that lower cooling rates give rise to larger pores, which are known to be detrimental to castings as potential failure initiation sites.

Kurzfassung

In der diesem Beitrag zugrunde liegenden Studie wurde eine Analyse der dreidimensionalen Porosität von Gussstücken einer Al-Si-Legierung mittels Computertomographie durchgeführt. Es wurde eine statistische Analyse gemacht, um die Porosität der Gussstücke nach Abkühlung mit hohen und niedrigen Geschwindigkeiten zu vergleichen. Es wurde beobachtet, dass die Abkühlraten die Bildung sowohl von großen als auch von kleinen Poren stark beeinflussen. Das Auftreten von kleinen Poren mit Abmessungen zwischen 0.00003 mm³ und 0.0004 mm³ kann in Gussstücken, die bei niedrigen Abkühlraten hergestellt wurden, bis zu sechsmal häufiger sein. Bezüglich großer Poren mit den Abmessungen zwischen 300 μm und 360 μm wurde beobachtet, dass niedrigere Abkühlraten größere Poren verursachen, die bekanntermaßen abträglich für Gussstücke sind, weil sie Ausgangstellen für Schäden sein können.

§Correspondence Address, Prof. Dr. Mohammad A. Irfan, Department of Mechanical Engineering, College of Engineering, Qassim University, PO Box 6677, Buraidah 51452, Al Qassim, Saudi Arabia, E-mail: mairfan@qec.edu.sa

Dr. Fahad Al Mufadi, born in 1969, did his PhD in Mechanical Engineering at Ohio University, USA in 2004. He has over 10 years of teaching and research experience. His current research interests include advanced materials processing, micro forming and CAD/CAM of dies. At his current position in Qassim University in Saudi Arabia, he is working on mechanical properties of forgings and castings.

Prof. Dr. Mohammad A. Irfan, born in 1962, did his PhD in Mechanical Engineering at Case Western Reserve University, Cleveland, OH, USA in 1998. Following his PhD, he worked for 2 years in the US industry. He has over 15 years of teaching and research experience. At his current position as Professor in Qassim University in Saudi Arabia, he is working on mechanical properties of permanent mold castings.

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Published Online: 2015-04-21

Published in Print: 2015-04-30

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https://doi.org/10.3139/120.110727