Application of fused deposition in controlled microstructure metal-ceramic composites

Purpose - Al-alumina interconnected phase composites were processed using the direct fused deposition process. These materials with tailored microstructures can find applications as structural materials with gradient properties. Design/methodology/approach - In this process, feedstock material with fused silica as a starting material was compounded at a high shear mixer and then extruded as a filament using a single screw extruder. Extruded filaments were used with a commercial fused deposition modeler, FDM 1650, to process controlled porosity green ceramic structures. Porous green ceramic preforms were subjected to binder removal and sintering cycles in furnace air. Controlled porosity sintered ceramic structures were infiltrated with Al 5052 metal by pressureless reactive metal infiltration to form an in situ Al-alumina structured composite. Findings - The main advantage for this approach is to control distribution of both metal and ceramic phases in the composite. During metal infiltration good bonding was observed between the metal and the ceramic phases. Composites were tested under both quasi-static and dynamic shock loading to evaluate their mechanical properties. Compression strength of these composites was 689 +/- 95 MPa. Originality/value - This paper describes application of the direct fused deposition process for fabrication of ceramic/metal composites where both macrostructure as well as microstructure can be controlled simultaneously. The paper also focuses on one of the potential application area for 5052-Al alloy.