Title screen

[References: 14 tit.]

The deformation behavior of alumina ceramics with multi-level pore structure and strain accumulation during cyclic compression tests with increasing load has been studied. It is established that the creation of a block structure in alumina ceramics, due to multilevel porosity and the effect of "zonal segregation", allows moving from brittle deformation behavior to quasi-plastic. Cyclic tests indicated the presence a hysteresis and allowed to determine the residual deformation (the limit of proportionality). It is shown that the residual deformation occurs after a stress of 13 MPa, which is approximately 0.3 of fracture stresses. Microanalysis of the fracture surface indicates that the fracture goes along the boundaries of the blocks, or in other words, through the pore channels. Analysis of the stress-train curves before beginning of plasticity showed that it can be divided into three parts with different slopes which define a "technical" modulus under compression test. Cyclic tests with increasing load indicate high resistance of alumina ceramics with multilevel pore structure to defects arising in its volume, which is not typical of alumina ceramics with unimodal or bimodal porosity.