High-temperature mechanical behavior of partially sintered ceramics

V. NECINA; S. GASS; M. H. TALOU; T. UHLIROVA; M. A. CAMERUCCI; A. G. TOMBA M.

JOURNAL OF MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2023

0022-2461

The high-temperature mechanical behavior (elastic properties, fracture strength, anddegree of irreversible deformation) of partially sintered alumina and zirconia ceramicswith different porosities and degrees of sintering was evaluated by (static) three-pointbending tests at 1100 °C, from which load-deflection curves were obtained.Furthermore, the elastic modulus obtained from these curves was compared toYoung’s modulus as measured via the impulse excitation technique. Bar-shapedspecimens were prepared by uniaxial pressing and sintering at 1100 °C, 1200 °C, 1300°C and 1400 °C for 2 h, and subsequently characterized via bulk densitymeasurements, total porosity calculations and electron scanning microscopy analysis.The effects caused by progressive sintering and the occurrence of irreversibledeformation due to the weak bonds (small sinter necks) between particles affected thevalues of the static elastic modulus, which resulted in values quite lower than thoseobtained by the impulse excitation technique. A very good correlation described with apower-law relationship was obtained between both type of modulus, dynamic andstatic one, in the whole range of sintering temperatures for the two evaluated porousceramics. In particular, the very fine (nanocrystalline) grain size and the tendency toagglomerate of the zirconia powder facilitated the irreversible deformation by grainboundary sliding.