Analysis of fatigue crack initiation and S-N response of model cast aluminium piston alloys

Mbuya, Thomas O., Sinclair, Ian, Moffat, Andrew J. and Reed, Philippa A.S. (2011) Analysis of fatigue crack initiation and S-N response of model cast aluminium piston alloys Materials Science & Engineering: A, 528, (24), pp. 7331-7340. (doi:10.1016/j.msea.2011.06.007).


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Fatigue crack initiation and S-N fatigue behaviour of hipped model Al7Si-Sr and Al0.7Si piston alloys have been investigated after overaging at 260oC for 100 h to provide a practical simulation of in-service conditions. The results show that hipping did not affect the S-N behaviour of Al7Si- Sr. This is attributed to the lack of significant change in porosity distribution in this alloy because of its low porosity levels even in the unhipped state. However, hipping profoundly improved the fatigue performance of alloy Al0.7Si due to the significant reduction in porosity. In this investigation, it was observed that porosity was rendered impotent as a fatigue crack initiator in both hipped alloys. Instead, fatigue cracks were observed to originate mainly from intermetallic particles (particularly the Al9FeNi phase) in both alloys and sometimes from oxide particles in Al0.7Si alloy. Fatigue cracking was also frequently observed at intermetallic clusters in hipped Al0.7Si. The observed scatter in fatigue life is discussed in terms of the size of fatigue crack initiating particles and the overall particle size distribution which follows a power law distribution function

Item Type: Article
Digital Object Identifier (DOI): doi:10.1016/j.msea.2011.06.007
Organisations: Engineering Mats & Surface Engineerg Gp
ePrint ID: 189723
Date :
Date Event
Date Deposited: 21 Jun 2011 07:22
Last Modified: 18 Apr 2017 02:01
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