Effective Young's Modulus of Ni-Al2O3 composites with particulate and interpenetrating phase structures: A multiscale analysis using object oriented finite element method

In this study effective Young's Modulus of Ni-Alumina composites were evaluated using object-oriented finite element method (OOFEM). Two different type of composites having particulates structure and interpenetrating phase structure were studied. Three samples of each type of composites having 40%, 60% and 80% Ni reinforced in Alumina were studied. The results obtained from OOFEM were compared with ultrasonic measurements reported in literature. For certain particle-reinforced composites, the elastic moduli measured ultrasonically did not obey the OOFEM. The mismatch was attributed to the presence of damage because of debonding between Ni and Alumina phases. This damage could be accounted for using OOFEM. Composites with damage were treated as porous material and modeled as three phase composites containing nickel, alumina and damaged phase. To match the Young's Modulus with the ultrasonic measurements, the percentage of damage pixels in composites were obtained. Local stress distribution was studied across the mesh of composites to understand the effect of porous microstructures.