Optimization of the production parameters and investigation of the properties of composites of metal and micro glass bubbles

The current study investigated an alternative, and new, type of syntactic foams. The cellular solids, prepared in the present study, consist of a metallic matrix containing a high volume fraction of thin walled hollow borosilicate bubbles. Concerning the composition of the composite, different combinations of raw materials were tested. As metallic matrix, common casting alloys such as AlSi9Cu3, Zn AC41A and AM50 were used; and as porous structure, hollow glass micro bubbles of different densities were investigated. Additionally and before starting the sintering and infiltration experiments, the density variation between the loose and beat bulk density of the glass structures was analysed. A simultaneous evaluation of the feasible density for each combination of composite was also done. Furthermore the sintering parameters of the S22 and K1 glass bubbles were optimized and a characterization of the sintering process and results was executed. After defining the best sintering parameters, the infiltration process with AlSi9Cu3 was done and, afterwards, some infiltration experiments with AM50 and Zn AC41A were also executed. Parallelly with the infiltration investigation the mainly important properties of the composites were tested. The tested properties were: hardness, compressive strength and thermal conductivity. Conclusively the new composites were compared to other syntactic foams, metal foams and some general materials.