Fatigue characterization of functionally graded ZA27 alloy syntactic foams

In this study, the fatigue properties of functionally graded metal syntactic foams (FG-MSF) are investigated under cyclic loading. The functionally graded foams are produced by controlling the spatial distribution of weak expanded perlite and stronger activated carbon particles within a ZA27 alloy matrix. As a reference, uniform metal syntactic foams containing only expanded perlite particles are tested alongside the functionally graded foams. These uniform foams are referred to as expanded perlite metal syntactic foam (EP-MSF). All samples are fatigue tested at three load levels in a compressive-compressive mode. The fatigue limits are evaluated using the staircase method and show similar values for both uniform and functionally graded foams. The Wo center dot hler curves at the failure criterion ccrit = 2% indicate almost identical numbers of fatigue cycles for FG-MSF and EP-MSF. The analysis of the deformation mechanism showed that the weaker EP layer controls the deformation mode of FGMSFs. Similar to EP-MSF, the samples deform in a brittle manner with the propagation of shear bands.