Oxidation of Ceramic Materials Based on HfB-SiC under the Influence of Supersonic CO Jets and Additional Laser Heating.

The features of oxidation of ultra-high-temperature ceramic material HfB-30 vol.%SiC modified with 1 vol.% graphene as a result of supersonic flow of dissociated CO (generated with the use of high-frequency induction plasmatron), as well as under the influence of combined heating by high-speed CO jets and ytterbium laser radiation, were studied for the first time.

Investigation of the Effect of Supersonic Flow of Dissociated Nitrogen on ZrB-HfB-SiC Ceramics Doped with 10 vol.% Carbon Nanotubes.

The method of fabricating dense ultra-high temperature ceramic materials ZrB2−HfB2−SiC−CCNT was developed using a combination of sol-gel synthesis and reaction hot pressing approaches at 1800 °C. It was found that the introduction of multilayer nanotubes (10 vol.%) led to an increase in the consolidation efficiency of ceramics (at temperatures > 1600 °C).

Investigation of Technological and Load Intensity Parameters of the Finishing Process of Materials on Equipment with Tools Translational Kinematics.

The regularities of the formation of the resulting raster tool trajectories based on Lissajous figures for the lapping process of planes are established. This makes it possible to maximize the cutting ability of the tool, which contributes to its more uniform wear and increased productivity and processing quality. Optimal parameters of productivity and roughness of the treated surface during lapping of zirconium ceramics are achieved through the use of ASM paste 28/20 µm.

A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test.

In order to predict the wrinkling of sheet metal under the influence of fluid pressure and temperature during warm/hot hydroforming, a numerical simulation model for sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of sheets under the through-thickness normal stress.

Discrete model of gas-free spin combustion of a powder mixture.

We propose a discrete model of gas-free combustion of a cylindrical sample which reproduces in detail a spin combustion mode. It is shown that a spin combustion, in its classical sense as a continuous spiral motion of heat release zones on the surface of the sample, does not exist. Such a concept has arisen due to the misinterpretation of the experimental data.

Dependence of the transition from Townsend to glow discharge on secondary emission.

, (1991)]]. Sijacić and Ebert stated that this transition strongly depends on secondary emission gamma from the cathode. We show here that the earlier results of von Engel and Raizer on the small current expansion about the Townsend limit actually are the limit of small gamma of the Sijacić and Ebert expression, and that for larger gamma the old and the Sijacić and Ebert new results vary by no more than a factor of 2.