Materials Science Forum Vol. 1037

Abstract: The article considers the influence of the surface geometry of a detail on the deposition of coating thickness in the simulation of electroplating processes. The methods for obtaining sets of points describing the surface of a detail are analyzed. Solving the inverse problem (recovering the 3D surface of a detail according to its 2D drawings) is the most promising method. The inverse problem solution is decomposed into simpler geometric problems: input data processing; obtaining primitives; obtaining the desired surface of a detail by applying logical operations to primitives. Mathematical statements are formulated and solution algorithms are proposed for solving these problems. The inverse problem solution is implemented through software. The distribution of the nickel coating thickness is shown for a detail, the surface of which is obtained by solving the inverse problem.

Abstract: The article presents the features of vibration processing of parts of electronic equipment in granular media. The method of combined processing by mixing granules with cutting and activating properties is considered as one of the ways to increase the intensity of vibration treatment. The increase in intensity is experimentally confirmed on the basis of a multivariate experiment with the construction of a regression model of the process.

Abstract: The joint research of scientists of two countries deals with cylindrical and surface grinding with abrasive wheels of heat-resistant steel Inconel 625 (KhN77TYu GOST 5632 – 72 Russian Federation standard), (analogues include Hastalloy, N07080, Alloy 80A, Nimonic 80A, 2.4952 ASTM B637/ASME SB637, UNS N07080). The article shows the results of studies of the features of high-temperature steel during grinding with a fastened abrasive. The results of experiments are given to determine the optimal characteristics of grinding wheels, grinding modes, cooling-lubricant fluids. Experimental data about geometric accuracy, surface roughness, resistance of wheels are demonstrated as well. The ways to prevent from defects during cylindrical and surface grinding of high-strength steel are proposed. The recommendations to increase the tool resistance and output of the process are given.

Abstract: The issues of processing high-alloy corrosion-resistant steels by the method of centerless cylindrical grinding are considered in the article. Experimental data on changes in the parameters of roughness and hardness of a workpiece depending on the depth of cut, the speed and the design features of a control wheel are presented. The change in the microhardness of a part depending on the depth of cut is analyzed. Much attention is paid to the study of thermal stress of the grinding process. Images of temperature changes in the cutting zone depending on the grinding wheel characteristics are shown. Conclusions in the form of practical recommendations for improving high-alloy steel processing by the method of centerless grinding are formulated on the basis of the results obtained.

Abstract: The authors conducted the study at micro-scratching of titanium, zirconium, niobium and molybdenum alloys. The content of the main element in alloys was from 99.5 to 99.7 %. Micro-cutting was carried out by specially prepared indenters with silicon carbide mono-crystals of a given shape. The state of the relief and the chemical composition of the wear area were studied using a scanning two-beam electron microscope. The micro-scratching speed was 35 m/s without cooling. The condition of the contact surfaces of silicon carbide and metals was studied at a magnification up to 100,000 times with the rotation and tilt of the microscope slide. The content of chemical elements was determined at individual spots of an object by scanning along the line and area. The authors also studied the condition of the wear area after micro-scratching of metals and after removal of metal adhesions by chemical etching. The intensity of metal transfer was determined by the average concentration of metal atoms at the wear area. The article also gives a classification of metals according to the intensity of transfer immediately after grinding and removal of metal adhesions. The influence of metal and the depth of micro-scratching on the morphology of the wear site is shown. It was found that molybdenum, having a low adhesive activity to silicon carbide, is able to penetrate microcracks and other surface defects during micro-scratching. The width of microcracks and the depth of metal penetration were determined

Abstract: Atomic force microscopy (АFМ) and high-precision scanning electron microscopy methods were used to study the surface of diffusion filter-membranes of alloy Pd₉₃Y₇. The formation of alterations in structure in one of membranes was established as a result from the homogenizing annealing at 900°C for 1 hours. It was found that the reversible doping of the membrane alloy with hydrogen caused the dispersion of the diffusion filter-membranes’ surface structure. Differences in changes by the surface structure are determined during the hydrogenation in directional and non-directional flow of hydrogen.

Abstract: It has been shown that account of elastic nonlinearity during the propagation of an acoustic wave in a solid lead to the appearance of a quadratic nonlinearity, which in its turn leads to the possibility of generating a wave of double frequency, the interaction of harmonics is asymmetric. The conditions under which nonlinear stationary waves are formed are considered. A phase portrait is constructed, and the dependence of the wavenumber of a nonlinear wave on its amplitude is estimated.

Abstract: This paper provides a comparative assessment of the results of modeling the processes of deformation and destruction of objects under uniaxial tension in the MSC.Marc and DEFORM software packages and in a full-scale experiment, as well as a study of the influence of the form factor of these objects and the form of unit cells on the fracture parameters in modeling and experiment.

Abstract: The calculation of the coefficient of dynamism of the contact interaction of bodies (lead balls and wheat grains with a moisture content of 11.5%) was carried out based on the hypothesis of equality of the work consumed during static and dynamic deformation of bodies, according to the formula:Θ=(S_o+S_u)/(S_od+S_u),where S_o – residual deformation of the body under static loading;S_od – residual deformation of the body under dynamic loading;S_u – elastic deformation under static and dynamic loading.The components of the formula were determined on specially designed devices:– on an electromechanical press with static interaction of bodies, at a deformation rate of 0,055 m/s, the following values were determined from the load – discharge diagrams: the value of elastic deformation S_u and the maximum residual deformation of bodies S_o.– on a vertical copra (at a contact interaction speed of 1-2 m/s) and a shock stand (at an impact speed of 11-15 m/s), the residual Sod deformation was determined by the size of the contact spot on the bodies after the impact.The calculated values of the dynamism coefficient were:for lead balls – 1,4-2,1;for wheat grains – 1,3-1,45.The results obtained indicate that the value of the dynamism coefficient increases with increasing impact velocity, with the same work spent on deformation, since the proportion of residual deformation in the total deformation of bodies decreases (bodies are strengthened).It is advisable to continue experiments to determine the coefficient of dynamism of bodies depending on the impact velocity, the configuration of the impact surface and the physical properties of the contacting bodies.

Abstract: An intelligent system has been developed to predict the fatigue strength of metallic materials over a wide temperature range. A neural network, properly trained, is a model of a dynamic system of fatigue failure of a part and is able to predict the values of the number of loading cycles to failure, as well as the onset of formation and growth rate of fatigue cracks for various test conditions, including at low temperatures.