Thermal expansion behavior of Ni-Al2O3 composites with particulate and interpenetrating phase structures: An analysis using finite element method

The thermal expansion behavior of Ni-Al2O3 composites was investigated up to 700 degrees C using object-oriented finite-element method (OOF). Composites having particulate structure and interpenetrating phase structure (IPC) were studied. Three samples of each type of composite structure, with 40%, 60% & 80% Nickel, reinforced in Alumina were studied. In the present work, the instantaneous coefficient of thermal expansion (CTE) was predicted using OOF and thermo-elastic models of Kerner & Turner and the results were compared with the experimental values reported in literature. The CTE of metal-matrix composites is significantly influenced due to the presence of voids & the plastic deformation of matrix. Composites with porous microstructure were modeled as three phase composites containing nickel, alumina and porosity and the percentage of porous phase was obtained. The thermal stresses resulting due to the CTE mismatch of constituents, were analyzed by plotting the thermal stress contours. (C) 2014 Elsevier B. V. All rights reserved.