Studying of the strength characteristics of the ZTA composites during fatigue loading

The paper presents the experimental results on the fatigue behavior of the ceramic composite Al2O3–ZrO2 at three-point bending during fatigue loading. The bending strength and flexural modulus are derived under static conditions at loading rate 3 mm/min. The fatigue strength and fatigue limit are investigated at a frequency of 4 Hz in three stress ranges: 0.9, 0.8 and 0.7 of the average maximum static bending strength. The ceramic samples sintered at 1650°C had porosity of 6.5% and showed the greatest fatigue limit with the high bending strength and flexural modulus: σben = 103.6 MPa, Eben = 39.04 GPa. The ceramic samples sintered at 1400°C had porosity of 21% and showed low resistance to fatigue loads with the low bending strength and flexural modulus: σben = 20.57 MPa, Eben = 14.54 GPa. The 3D X-ray tomography investigation showed that the ceramic samples had a relatively large numbers of defects, such as zirconia aglomerates, pores and microcracks. The latter are the sources of fatigue cracks that impair the fatigue strength of the ZTA ceramic composites.The paper presents the experimental results on the fatigue behavior of the ceramic composite Al2O3–ZrO2 at three-point bending during fatigue loading. The bending strength and flexural modulus are derived under static conditions at loading rate 3 mm/min. The fatigue strength and fatigue limit are investigated at a frequency of 4 Hz in three stress ranges: 0.9, 0.8 and 0.7 of the average maximum static bending strength. The ceramic samples sintered at 1650°C had porosity of 6.5% and showed the greatest fatigue limit with the high bending strength and flexural modulus: σben = 103.6 MPa, Eben = 39.04 GPa. The ceramic samples sintered at 1400°C had porosity of 21% and showed low resistance to fatigue loads with the low bending strength and flexural modulus: σben = 20.57 MPa, Eben = 14.54 GPa. The 3D X-ray tomography investigation showed that the ceramic samples had a relatively large numbers of defects, such as zirconia aglomerates, pores and microcracks. The latter are the sources of fatigue cracks that impa...