Effect of sintering temperature on residual stress, microstructure and mechanical properties of TiC-HfN/TiC–TiN laminated ceramic

Abstract

The TiC-HfN(TH)/TiC–TiN(TT) laminated ceramics were fabricated by the layer-making and hot press sintering technology, and effects of sintering temperatures on residual stress distributions and properties had been investigated. Layer thickness of these ceramics was in accord with the design thickness. Residual compressive and tensile stress were alternant with the alternation of TH and TT in these ceramics, and as sintering temperature rose, they increased, respectively. Grain was smaller in TH than in TT for these ceramics. The difference of the average grain size between TH and TT became bigger as the sintering temperature rose. And the suitable grain size difference could make the ceramic possess higher flexural strength. The TiC-HfN/TiC–TiN ceramic sintered at 1550 °C possessed the better comprehensive mechanical properties: its flexural strength was (927 ± 18) MPa; its hardness and fracture toughness in TH were (16.54 ± 0.31) GPa and (7.36 ± 0.18) MPa·m1/2, respectively; those in TT were (20.31 ± 0.22) GPa and (6.28 ± 0.13) MPa·m1/2, respectively. This research conclusion has great significance for design and fabrication of the laminated ceramic with high mechanical properties.