Abstract
The effective elastic moduli of cermets consisting of ceramic particles located in a metal are discussed and compared with the properties of sintered matrix materials. New experimental work shows that the properties depend significantly on the degree of bonding between the phases. If this is strong, the nominal Young's modulus increases with concentration; if not (as in uranium oxide-stainless steel) it diminishes, but less rapidly than that of a porous steel. The rigidity modulus falls continuously with the proportion of the ceramic phase present, because local plastic deformation occurs rapidly in shear.
The decrease in tensile strength with concentration has previously been explained in terms of the packing arrangements of spheres, which reduce the load-bearing area of the matrix cross-section. A tentative equation is derived which shows that stress concentrations near the inclusions may also play an important role in determining the effective mechanicalstrength at high ceramic contents.
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