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The effect of cerium on high‐cycle fatigue properties of die‐cast magnesium alloy
Author(s) -
YANG Y.,
LIU Y. B.
Publication year - 2007
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2007.01184.x
Subject(s) - materials science , dimple , microstructure , alloy , metallurgy , scanning electron microscope , magnesium alloy , fracture (geology) , fatigue limit , cerium , cracking , porosity , grain size , die (integrated circuit) , composite material , nanotechnology
The effect of cerium (Ce) on high‐cycle fatigue behaviour of die‐cast magnesium alloy AZ91D was investigated. Mechanical fatigue tests were conducted at the stress ratio, R = 0.1 on specimens of AZ91D alloys with different Ce additions. The microstructure and fatigue fracture surfaces of specimens were examined using a scanning electron microscope (SEM) to reveal the micromechanisms of fatigue crack initiation and propagation. The results show that the grain size of AZ91D is refined, and the amount of porosity decreases and evenly distributes with the addition of Ce. The fatigue strength of AZ91D evaluated by the up‐and‐down load method increases from 96.7 MPa to 116.3 MPa (1% Ce) and 105.5 MPa (2% Ce), respectively. The fatigue cracking of AZ91D alloy initiates at porosities and inclusions of the alloy's interior, and propagates along the grain boundaries. The fatigue fracture surface of test specimens shows the mixed fracture characteristics of quasi‐cleavage and dimple.