Effect of particle size and volume ratio of ceramic hollow spheres on the mechanical properties of bimodal composite metal foams

High performance bimodal composite metal foams (BCMFs) have been produced by low-pressure infiltration of EN-AW Al99.5 and EN-AC AlSi12 alloys into two sets of different nominal diameter (2.4 mm and 7.0 mm) Al2O3 ceramic hollow spheres (CHSs) in a total of five different volume ratios arranged in random closed packing distribution. The structure of the BCMFs has been studied by X-ray computer tomography and scanning electron microscopy. The mechanical properties were mapped by standardised quasi-static compressive tests. The structural investigations of the BCMFs showed proper infiltration and a higher filling ratio compared to unimodal composite metal foams. Given a specific matrix material, different volume ratios of the spheres do not have a substantial effect on the mechanical properties of the BCMFs. The mechanical properties were found to be predominantly filling rate (the volume fraction of the CHSs divided by the total volume of the sample) dependent.

Automated summary

This study focuses on the production of high performance bimodal composite metal foams by infiltrating EN-AW Al99.5 and EN-AC AlSi12 alloys into two sets of Al2O3 ceramic hollow spheres with different diameters. The mechanical properties of the BCMFs were found to be dependent on the filling rate, rather than the volume ratio of the spheres. The structural investigations showed proper infiltration and higher filling ratio compared to unimodal composite metal foams.