A study of the dissipative properties of homogeneous materials deposited as coatings. Part 2. Copper condensates with different microstructural characteristics

Abstract

and N. S. Kosenko bThe dependence of dissipative properties of copper condensates on the grain size has been studied. Condensates with a grain size of 0.9-3.7 μm were obtained by electron-beam vapor deposition of copper as coatings on a titanium substrate. The oscillograms of damped bending vibrations of the substrate-coating system were recorded at a frequency of 140-150 Hz in the temperature range 20-350°C. The values of true logarithmic vibration decrement for copper condensates were determined by the self-consistent calculation of energy loss factors of the substrate and coating by the method proposed in the part 1. It has been shown that the amplitude dependences of the true logarithmic vibration decrement of copper condensates at room and elevated temperature are largely determined by their structure.

Dynamic Processes of Self-Organization in Nonstationary Conditions of Friction

“…Te established positive efect of the formation of nearsurface layers with a fne-grained structure on the wear resistance of friction pairs and the reduction of specifc work of friction during operation in nonstationary conditions can be explained by the shielding properties of the boundary flms of the lubricant due to the manifestation of the plasticizing efect of surface-active substances on the surface layers of investigated steel surfaces with their subsequent strengthening under an increase in the density of dislocations. Work [33] observed a decrease in energy absorption rates of metals with a decrease in their grain volume (in the range from tens to several micrometers), which is due to a decrease in the level of internal friction.…”

Influence of Fe-additives on the microstructure and mechanical properties of vacuum copper condensates

“…To reduce the energy losses due to metal friction in the points of substrate clamping, damping oscillograms were recorded after "training" of the "fresh" samples -their cyclic deformation up to N = 25000 cycles at amplitude A exceeding the initial amplitude of LD measurement by 15-20%.The obtained amplitude dependencies of ı(A) characterize the energy dissipation in the "coating-substrate" system. Since with such a schematic of measurement deformation of the coating material along the sample length is non-uniform, then to determine the amplitude dependence of the intrinsic damping decrement of coating material ı(ε), where ε is the amplitude of homogenous strain of coating material, numerical methods of calculation of this value by ı(A) data were used, which are briefly described in [15] and in greater detail in [16]. 1 VT1-0 titanium alloy (99.7 wt.% Ti) is commercially pure titanium.…”

Dissipative properties of nanostructured materials

“…The microstructure characteristics of condensates were determined using scanning and transmission electron microscopy. The dissipative properties of coating materials (plots of the true energy loss factor ψ m of material against amplitude at different temperatures) were calculated on the basis of plots of vibration decrement of the substrate-coating system against amplitude by the method proposed earlier [9,10]. The experimental measurement of the plot of vibration decrement of the substrate-coating system against amplitude was performed by the method of free damped vibrations of flat specimens supported as cantilevers on a unit equipped with a system for heating specimens to predetermined temperature [11].…”