In work mechanical properties of polyimide films analogue kapton H (manufactures of the People's Republic of China) with different thickness in the temperature interval 77-293 K and deformation speed interval 10-4-10-3 s-1 are carried out. It is established, that the films are in a forced elastic state at both temperatures of deformation. Contributions to total deformation such as elastic, high elastic (reversible at temperature of test and delay) and irreversible components are determined. It is detected, that relaxation processes which are connected with the contribution of elastic delayed deformation and are accompanied with reduction of their length, take course at exposure at a room temperature of samples after destruction or preliminary deformation. Full removal high elastic delayed deformation occurs after heat treatment at 623 K. Sensitivity of a limit of forced elasticity s в and the contribution of elastic deformation which is reversible at test temperature to deformation speed are established. Influence of the scale factor (thickness of a film) on the mechanical characteristics, which are amplified with downturn of temperature is registered.

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620.22:539.3/4 and S. M. DergunWe present results of studying mechanical properties of four groups of metallic and nonmetallic composite materials in a temperature range of 300-4.2 K. Types of glass-reinforced and carbonreinforced plastics with the best low-temperature strength and elastic characteristics have been specified. A deterioration of the strength characteristics of boron-fiber-reinforced aluminum alloy after temperature cycling in the temperature range 20-443 K has been detected. It has been shown that superconducting composites with ultra-fine filaments, fabricated by hydrostatic extrusion without intermediate annealings, possess optimal combination of mechanical and electrical characteristics.Keywords: metallic and nonmetallic composite materials, strength characteristics, hydrostatic extrusion method.Introduction. Composite materials (metallic and nonmetallic) with a broad range of combined components of different structure (particle-, fiber-, ply-strengthened) and hence operational characteristics possess huge potentialities of use in multi-section structures and devices of cryogenic-vacuum and aerospace equipment both as structural and as functional materials with tailor-made properties.Glass-reinforced and carbon-reinforced plastics and boron-reinforced metal composites are most commonly used structural composite materials for aerospace purposes. Their usage ensures a high specific strength and rigidity under different types of strain (tension, compression, bending) and at the required level of thermophysical characteristics.Among the functional composite materials that are used in cryogenic-vacuum equipment, in particular in cryogenic electric machine industry, superconducting (SC) composites are noteworthy. These materials must combine both good electrical and magnetic and the best mechanical characteristics (plasticity, strength) in the operating temperature range. Composites based on such bcc deformable superconductors as Ti-Nb are most reliable. Composites based on these alloys are cables consisting of tens of thousands of fine SC fibers pressed into a copper matrix.Optimization (for operation under extreme conditions) of the set of mechanical and functional characteristics of composites is impossible without obtaining systematic data on their mechanical properties in a wide temperature range up to ultra-low temperatures.In this work, mechanical properties of four groups of commercial structural and functional composite materials were studied in a wide temperature range (300-4.2 K) under different types of loading (tension, compression and bending) to obtain absolute values of characteristics, to establish general regularities of their variation with temperature, and to choose the best materials for operation under specific operation conditions. Materials and Methods of Investigation. The composites under investigation were divided into four groups according to the type of the combined materials.Group 1: glass-fiber-reinforced structural nonmetallic composites: VPS-7, VPS-13, KAST-V and DSV....

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