Investigation of mechanical properties of spinelcontaining glassceramic materials

This work aims to study the mechanical properties of spinel­based glass ceramics in relation to their structure. The tasks of the work are: comparative analysis of transparent high­strength ceramic and glass­ceramic materials; study of the properties of spinel­based glass­ceramic materials in connection with their structure; recommendations on the use of high­strength glass­ceramic materials and prospects for their development. Application areas of spinel­based ceramic materials as multifunctional products were analyzed. The perspective of using glass­ceramic materials as protective elements of optics, aviation and ground transport was investigated. The presence of the crystalline phase was established using X­ray phase analysis, which was carried out at the DRON—3 installation. Petrographic studies were carried out using an optical polarizing microscope NU—2E. The Vickers hardness and the crack resistance index were determined by indenting the Vickers pyramid with a load of 5000 g on the pyramid for 10 measurements using the TMV—1000 device. Impact toughness was determined according to (EN1288—1:2000). The density of materials was measured by the method of hydrostatic weighing in toluene. The modulus of elasticity of materials was investigated using the device “Sound—107” by the method of determining the resonance frequency of oscillations with a relative error of ≈ 0.2 %. Based on a detailed analysis of the structure of glass­ceramic materials, the composition of magnesium­aluminosilicate glasses for obtaining high­strength glass­ceramic materials with high mechanical properties and adjustable light transmission has been substantiated. The technological modes of cooking and heat treatment of glass­ceramic materials were selected. The priority of forming a self­bounded micro­ and nanostructure of glass­ceramic materials under conditions of low­temperature heat treatment to ensure their high mechanical properties was shown. The determining influence on the optical and mechanical properties of glass­ceramic materials of spinel crystalline phases and their dimension, as well as the formation of an oriented structure by directional crystallization, was established. Mechanical (HV = 8.7 ÷ 10.5 GPa; K1C = 4.0 ÷ 6.0 MPa · m1/2; σст = 550 ÷ 650 MPa; KCU = 4.0 ÷ 5.5 kJ/m2) and optical properties of glass­ceramic materials (T = 72 %) and their density (ρ = 2550 ÷ 2850 kg/m3). A comparative evaluation of known transparent ceramic and glass­ceramic materials indicates the expediency of using the developed materials both in the glazing of aviation equipment and for the protection of special ground equipment.