Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Composites Theory and Practice

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Zirconium dioxide/tungsten carbide composite - influence of sintering technique on phase composition and microstructure

Pędzich Zbigniew, Wilmański Alan, Wojteczko Agnieszka, Komarek Sebastian, Kozień Dawid, Klimczyk Piotr

Composites Theory and Practice

2025

R. 25, nr 1

30--37

The paper presents the results of a comparative experiment on sintering a particulate composite in the ZrO2/WC system containing significant amounts of carbide additive (20 or 50% by volume) utilizing spark plasma sintering (SPS) or high pressure high temperature (HPHT) techniques. The experiment was conducted using commercial zirconia and tungsten carbide powders. The main aim of the experiment was to verify if it was possible to use the HTHP technique to manufacture composite parts in order to increase the efficiency of the production process. The obtained results showed that the final microstructures of the composites produced by SPS and HPHT differ significantly in their phase composition and microstructure. The materials received by the HPHT process after consolidation contained a large volume of monoclinic zirconia phase, which was a serious disadvantage of the consolidated material due to strong susceptibility to cracking. Furthermore, the short time of sintering prevented the tungsten carbide grains from modifying their shape during the sintering process. The SPS process took more time, but in result the microstructure of the composites contained a non-transformed tetragonal zirconia phase and the carbide grains transformed their shape into convex and isometric ones.

ATZ composites resistant to subcritical crack propagation

Wojteczko Agnieszka, Grabowy Marek, Wilmański Alan, Komarek Sebastian, Kozień Dawid, Pyda Waldemar, Maria Rosa, Capote Pena, Pędzich Zbigniew

Composites Theory and Practice

2024

R. 24, nr 3

194--199

ATZ (alumina toughened zirconia) particulate composites are materials which utilize the phenomenon of residual thermal stresses arising during cooling from the sintering temperature to normal conditions. Since the stresses in zirconium dioxide grains are tensile, they increase the susceptibility to transformation of the tetragonal phase into the monoclinic one, a phenomenon which is used to strengthen the material, i.e. to increase its resistance to cracking. The paper presents the results of research on composites that were manufactured by means of special technology using the sintering of a mixture of ZrO2 powderswith various contents of the stabilizing oxide Y2O3. These materials, thanks to a significant reduction in grain size, demonstrate excellent mechanical parameters, strength and resistance to brittle fracture. Moreover, it was found that incorporating alumina grains in the zirconia matrix can cause the distribution of stress to significantly reduce the tendency to subcritical cracking, which is a high risk for oxide ceramics. It was found that for some ATZ composites the phenomenon of subcritical cracking was inhibited in both air and water environments.