Crack growth resistance of ZrO2-(3-8) mol% Y2O3 ceramics was investigated. Young's modulus by the ultrasonic flaw detection method were determined. Vickers hardness and parameters of cracks after Vickers indentation were obtained. Based on the Young's modulus values, Vickers hardness, and parameters of cracks, the fracture toughness of the investigated ceramics was calculated using 9 different equations of the Vickers indentation method.
This paper is devoted to the results of deformation characteristics of concrete and reinforced foam concrete with fiber polypropylene fiber. Tests were carried out by the standard method and a method based on the values of equality elastic modulus of concrete in compression and tension using a chart based "stress-strain".
The results are given on the basis of an experimental research on firmness and deformability of normal sections of concrete beams reinforced with frameless reinforcement and rod reinforcement class A400C without prestressing. These experiments and comparing them with calculations according to current regulations give an opportunity to assess the convergence of the results and draw conclusions about the possibility of rational design of ceramic block bending elements with double reinforcement in the area of the normal forces.
This article presents the results of research crack resistance concrete after exposure to water saturation-drying cycles on the criteria of fracture mechanics. Presented values of power and energy characteristics of crack and deformation diagrams of concrete after water saturation-drying for 100, 180 and 360 cycles.
Zinc oxide has numerous commercial device applications. Polycrystalline ZnO varistors, for example, are widely used in high voltage and power-related applications in industries such as microelectronics. One of the ways to control the properties of ZnO is its annealing in various environments, including oxygen, which leads to increased hardness and fracture toughness of ceramics.