Effect of matrix grain growth kinetics on composite densification

The effect of matrix grain growth kinetics on the densification behavior of a particulate composite has been investigated, Large alumina inclusions mere added to two types of zirconia matrices having different grain growth kinetics, i.e., Zr(SY)O-2 and Zr(3Y)O-2. Despite the evolution of different grain sizes, both matrices reached an end-point relative density of 0.92 and 0.94, respectively, even though they contained 0.25 volume fraction of inclusions (based on total solid volume). However, the morphology and spatial distribution of the residual pores were distinct, The Zr(SY)O-2 matrix, which developed very large grains, had a dual microstructure with porous regions surrounded by a connective, denser region, as previously reported fur an alumina matrix containing zirconia inclusions. Conversely, the Zr(3Y)O-2 matrix was fully dense and uniform, but the composite contained large cracklike voids at inclusion/matrix interfaces, The large opening displacement of these crack-like voids locally relaxed the constraint to matrix shrinkage imposed by the inclusion network.