Sintering of TiO ₂ –Al ₂ O ₃ Composites: A Model Experimental Investigation

Abstract

In recent theoretical work we have shown that the sintering of a composite is strongly affected by the shear deformation of the continuous phase. This phenomenon was studied experimentally in a model system consisting of a TiO 2 matrix dispersed with nondensifying agglomerates of Al 2 O 3 . The results of this study are reported here. Several interesting results were obtained: (a) The experimentally obtained sintering rate of the composite could be successfully predicted by measuring the concomitant shear and densification rate of the matrix phase in a sinter‐forging experiment and using the developed analysis; (b) the densification rate of the composite changed with the volume fraction of the dispersed phase, but was unaffected by the size of the dispersed phase; and (c) processing flaws appeared to form only when the size of the dispersed phase was greater than about 10 μm. A technique for measuring the parameter β, which was used to correlate theory and experiments, is described. The procedures used for preparation of powders (from alkoxides) and the green compacts are also described in detail.