Mechanical characterization in PSZ/NiCrAlY composites fabricated by plasma activated sintering

Ceramic (partially stabilized zirconia: PSZ) and metal (NiCrAlY) monoliths, and PSZ/NiCrAlY composites were prepared at each sintering temperature using plasma activated sintering (PAS), of which mechanical properties were characterized with modified small punch (MSP) tests. Effects of sintering temperature on density and hardness in the composites decreased with the volume fraction of NiCrAlY, showing a gradual change of density and hardness in the intermediate compositions. The composites over 60 vol%-NiCrAlY showed an abrupt increase in fracture toughness. Even in PSZ monolith, higher fracture toughness of 10 MPa.m(1/2) could be obtained, which was due to the merits of PAS, such as a short sintering time and a rapid heating rate. Mechanical properties of PSZ/NiCrAlY composites were dominantly controlled by sintering temperature and NiCrAlY volume fraction, showing the traditional brittle behavior in PSZ monolith and the combined behavior between brittleness and plasticity up to 80 vol%-NiCrAlY composites. Sintering temperature indicated ultimate properties at each composition showed continuous change from 1400 degreesC in PSZ monolith to 1200 degreesC in NiCrAlY monolith, showing maximum difference of 200 degreesC, which was the optimized gradient temperature for the co-sintering of PSZ and NiCrAlY monoliths, and composites. (C) 2000 Elsevier Science B.V. All rights reserved.