Microstructure and mechanical properties of metal/ceramic microlaminate composites

The microstructure and mechanical properties of metal (NiCoCrAl)/ceramic (Y₂O₃-ZrO₂) microlaminate composites produced by EB-PVD was investigated. The results showed there were flat and distinct interfaces between metal and ceramic layers. Metal layers were found to consist of γ phase and has a relatively large equiaxed grain structure. While ceramic layers included cubic and tetragonal phases, in which a small columnar grain structure was observed. Furthermore, some evenly distributed micropores in the upper part of metal layers were also seen. The microlaminates exhibited brittle-like behavior without macroscopic plastic deformation in room temperature tensile tests. Examination of fracture surfaces from the samples revealed that the metal layers blunted cracks in the ceramic layers and that delamination at interfaces between layers occurred.