DESIGN OF MIXTURE EXPERIMENTS OF Al2O3 -TiB2 -TiC COMPOSITES: PART 1 -PREDICTION OF RELATIVE DENSITY AND FLEXURAL STRENGTH

Ten minutes after spark plasma sintering of 10 different mixtures at 1700 degrees C, 47 MPa, their relative density and flexural strength were analyzed in Minitab. Different regression models were obtained for each property. The behavior of relative density and flexural strength was explained by two quadratic models RDQ and FSQ, which were adequate with a statistical significance level of p = 0.05. Based on the models RDQ and FSQ, contour plots were made in the Al2O3-TiB2-TiC simplex for a visual representation of the predicted results. These contour plots show the zones corresponding to values of relative density > 99%, and flexural strength > 500 MPa. Combining these zones, it was possible to determine the region of the Al2O3-TiB2-TiC simplex, which simultaneously correspond to the relative density and flexural strength of sintered samples greater than 99%, and 540 MPa, respectively. The RDQ and FSQ models were additionally tested at three new points, revealing that additionally experimental values fit well into the predicted by Minitab intervals. Therefore, the RDQ and FSQ models can be used for the relative density and flexural strength prediction of Al2O3 -TiB2 -TiC composites sintered as described.