A Study on Tensile Properties of NiCoCrAl/YSZ Multiscalar Microlaminate

Abstract

One multiscalar microlaminate (MSML) with 5 thick layers of NiCoCrAl whose thickness were different interspersed with 66 thin layer stacks of NiCoCrAl/YSZ was fabricated by EB-PVD. Uniaxial tensile testing was performed and fracture was examined using SEM. The results show that the microlaminate exhibits brittle-like behavior without macroscopic plastic deformation in room temperature tensile tests and the maximum engineering stress is 212MPa. Examination of fracture surfaces from the samples reveals that ceramic layers fail by intergranular brittle fracture between columns, but metal layers display features of both ductile and brittle fracture. It is also found that the thicknesses of metal layers have a great effect on their failure modes. And interfacial debonding and bridging metal layers are observed. Moreover, the resistance of crack propagation in the microlaminate is discussed.