On the mechanical anisotropy of the compressive properties of aluminium perlite syntactic foam

A novel metallic syntactic foam is produced using a counter-gravity infiltration casting method. To this end, expanded perlite particles are combined with an aluminium alloy matrix. This enables close control of geometry at a relatively low production cost. The mechanical properties of the material are studied using finite element analysis. Numerical calculation models are generated directly from micro-computed tomography in order to capture their complex internal geometry. For verification purposes, numerical results are compared with experimental measurements of similar samples where available. But in contrast to experimental testing the numerical analysis is non-destructive and hence allows the repeated testing of samples in multiple loading directions. Thus, material anisotropy can be investigated for the first time. To this end, the quasi-elastic gradient, the 1% offset yield stress and the plateau stresses are obtained from virtual compression tests in three perpendicular directions (one coincides with the casting direction). Results indicate a weak anisotropy of the mechanical properties.