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Chigrinova N.M.,National State University Institute of the Metal Powder Industry
Surface Engineering and Applied Electrochemistry | Year: 2010

The analysis of the physical processes at various combinations of external impacts on the material in microplazmaspark alloying (MPA, MPA + USM, USM + MPA + USM) has been carried out in the present paper. Physical models for the microplasma electrode erosion and the cooling down of a droplet of the molten anode material in the MPSA process have been developed. As a result of the analysis of a numeric solution of the problems on heat conduction with a powerful point heat source of heat release and cooling down without sources, it has been established that the droplet cooling time for the eroded anode is markedly less than the other time parameters specifying the alloying process. There has been solved the problem of the determination of the optimum values of the pulse duration and the pause between the electrospark discharges that provide for the maximum anode erosion rate. A physico-mathematical model in the form of the small vibrations' theory with the corresponding algorithm and software realized in the Mathematica software package have been developed for the experimental data interpretation from the positions of the physical mechanisms. With the optimality methodology application, the possibility for the solution of the multifactor (the input parameters are the volt-ampere and time specifications, and the output parameters are the anode erosion rate and the fraction of the hardened droplet of the eroded anode material) problem of the control of the MPSA + USM joint process for obtaining a quality strengthened surface has been demonstrated. © 2010 Allerton Press, Inc. Source


Chigrinova N.M.,National State University Institute of the Metal Powder Industry | Kuleshov A.A.,National State University Institute of the Metal Powder Industry | Nelaev V.V.,National State University Institute of the Metal Powder Industry
Surface Engineering and Applied Electrochemistry | Year: 2010

The analysis of the physical processes in microplasmaspark material processing based on the effects of the electrodischarge plasma and mechanical impact with a varying intensity (MPA, MPA + UM, UM + MPA + UM) was carried out. The impossibility of a universal theory's construction describing the peculiarities of the above processes and being grounded on the basic principles of solid state physics was ascertained due to the given analysis. A new integrated approach valid both for the description of each of the described combined processing variants and for their comparative analysis is proposed, and it seems applicable for their parametric optimization. This approach for the physical interpretation of the experimental data set is based on the assumption that, during the transition from one mode of the cathode processing to another (from MPA to MPA + UM and to UM + MPA + UM), the initial structure state of the processed surface (that of the anode) undergoes an integral change that determines the structurization peculiarities at the subsequent alloying. The high correlation of the resilience properties, the resistance forces, the oscillation system's inertance, and the maximum values of the mechanical energy with the resultant properties of the coatings formed at various energies and mechanical impact intensities during the alloying has been noted. © Allerton Press, Inc., 2010. Source

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