ISSN:
1573-9139
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Conclusions Using the method of pure bending, we studied the steady-state (stationary) creep of the single-phase and the two-phase ceramics belonging to the ZrO2-CaO system in the 1300–1600°C and 2–32 N/mm2 ranges; the CaO content of the experimental ceramics varied from 12 up to 50%. The ratio of the strain rates in the two-phase region of the phase diagram (a mixture of the cubic solutions of ZrO2 and calcium zirconate CaZrO3) amounts to $$\dot \varepsilon _{25} :\dot \varepsilon _{35} :\dot \varepsilon _{45} = 1:14:13$$ at 1400°C and 4 N/mm2 and 1:5:3.8 at 1500°C and 2 N/mm2. The stress parameters and the activation parameters of creep (the stress exponent and the effective activation energy) were determined and their dependence on the phase composition of the experimental specimens was evaluated. The possible deformation mechanisms during the creep regime were discussed. It was shown that in the single-phase specimens consisting of cubic solid solutions, the mechanisms of diffusional-plastic (viscous) flow in the body of the grains, conservative dislocation slip, and creep induced by the formation of cracks operate. The values of the stress exponent of the two-phase specimens (n ≈1.3·1.6) indicate the occurrence of grain boundary sliding or the crack-induced creep mechanism. In the ceramic consisting of calcium zirconate, the combination of a relatively high activation energy for creep and the parameter n ≈ 2 indicates the dislocation nature of the high-temperature deformation process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01292545
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