Microwave-assisted combustion synthesis and compaction of intermetallic-based functionally graded materials: Numerical simulation and experimental results

The use of microwave (MW) energy as an ignition source for combustion synthesis and compaction of intermetallics-based functionally graded materials (FGMs) is suggested. Numerical simulation was used to investigate the temperature distribution in reacting powders before, during, and after combustion synthesis, showing that microwaves are capable of continuing to convey energy to the reactants and products, despite an adverse temperature gradient. Examples of the application of Microwave-Assisted Combustion Synthesis (MACS) are reported, involving principally neat intermetallic-based FGMs belonging to the CoAl-NiAl system, both as free-standing samples and as coatings on titanium Grade 5 alloy. Some other preliminary results on the reliability of the here proposed experimental approach to the synthesis of free-standing samples based on intermetallic-matrix ceramic particles reinforced FGMs are presented.