Прочностные свойства циркониевой керамики, упрочненной оксидом алюминия, с добавлением диоксида кремния

The effect of alumina and silica on strength of zirconia ceramics, stabilized with calcia, was studied. We have established the optimal concentrations of the components in the CaO-ZrO2+Al2O3+SiO2 system; these concentrations correspond to the highest flexural strength of 980±70 MPa. The optimal concentration of alumina is 5 wt.% in absence of silica. In terms of compressive strength the highest values of 2.44±0.15 MPa were obtained when concentration of alumina was 5 wt. % and content of silica was 5 mol. %. Stress-strain diagrams indicate presence of plasticity in the materials containing 4-5 mol. % SiO2 by having a yield plateau

Features of switching autowaves of localized plasticity in FCC alloy

The kinetics of deformation processes at the yield plateau in the aluminum alloy 1550 studied. It is established that in the general case, the motion of the Lüders band fronts occurs discretely and only in the phase of sample unloading. Continuous motion of the deformation fronts is possible if the rate of relaxation of the applied stresses due to the test machine is greater than or equal to the rate of their decline, controlled by internal processes at a lower scale level. The discrete motion of the Lüders fronts in the 1550 alloy suggests that they are not pure autowaves of switching.