Influence of Residual Thermal Stresses on the Properties of the NiAl Matrix Composites Reinforced with Ceramic Particles
One of the most important problems in both the fabrication and exploitation of ceramicmetal composites are residual thermal stresses. The paper presents the results of a numerical analysis (by the Finite Elements Method) of the stress state induced in the NiAl matrix composites reinforced with spherical particles of a ceramic phase (Al2O3, ZrO2, TiC), including examinations of the dependence of this stress state on the volumetric fraction of the ceramics (20 to 40vol.%). The stress state prevailing in this composite appeared to be complex. In all the samples, the stresses active in the ceramic regions were compressive whereas those active in the metal matrix were tensile in the circumferential direction and compressive in the radial direction. An increase of the ceramic volumetric fraction resulted in an increase of the tensile stresses in the NiAl matrix and a decrease of the compressive stresses in the ceramic particles. These theoretical results were verified experimentally by examining the properties of the NiAl-Al2O3, NiAl-ZrO2 and NiAl-TiC (20 and 30 vol.% fraction of the ceramics) composites produced by hot-pressing. The microstructure, density, and bending strength of these composites were examined, and the results are discussed in the paper.
Pietro VINCENZINI, Sheldon WIEDERHORN and Paolo COLOMBO
D. Kaliński et al., "Influence of Residual Thermal Stresses on the Properties of the NiAl Matrix Composites Reinforced with Ceramic Particles", Advances in Science and Technology, Vol. 65, pp. 21-26, 2010