Duplex ceramics: I. Stress calculations, fabrication and microstructure

Analysis of stress field in Al2O3-ZrO2biomaterials by finite element method

“…The cracks are propagated in the zones of weak energies with a deviation of the cracks induced by skirting of the black spherical zones and zones put in compression in blue. Similar phenomenon was already observed in experiments reported by Lutz [11][12][13].…”

“…According to the conditions considered by Lutz [13], the calculated pressures for optimum Al 2 O 3 -x%ZrO 2 ceramics are reported in figure 4.This internal pressure decreases when the R B /R A ratio increases. However, this pressure also increases with zirconia content such as reported elsewhere [15].Then, we conclude that Al 2 O 3 -35%ZrO 2 bioceramic is considered as the most selected zirconia content in view of suitable rupture with lower internal pressure than 1000 MPa [14].…”

Crack growth in non-homogeneous transformable ceramics. Part I: Constrained straight cracks

“…Confronting the Duplex results in Figures 11 and 12 with the Figures 8 and 9, respectively, for the corresponding cases with a smoother distribution, it is seen that the concentration in clusters actually improves the toughness by a factor of 2 to 2.5. These findings, in retrospect, may motivate the practical development of Duplex materials where relatively large (10-50#m) spherical t-ZrO2 zones are dispersed in a ceramic matrix, as discussed in [5,27,28]. For these materials, experiments show that the toughness is increased, but the strength of the material is decreased, compared to conventional ZTA materials.…”

“…The value of AK TIp is computed numerically on the basis of the integral formulation (27) and (28), with a 13 point Gaussian-integration within each element. However, near the crack Crack growth, Part I: Constrained straight cracks 259 tip the integration is carried out analytically to take care of the singularity in (27) at the tip.…”

“…However, near the crack Crack growth, Part I: Constrained straight cracks 259 tip the integration is carried out analytically to take care of the singularity in (27) at the tip. Further details may be found in [14].…”