International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper focuses on the degradation of molds that are used for the technology of high-pressure casting of Al and its alloys. The method of high-pressure casting of aluminum products is one of the widely used production methods, which at the same time meets the requirements for precision and productivity in the production of cars and various mechanical parts. In the high-pressure casting process, the molds are exposed to various thermal and mechanical loads, where the molds and their shaped parts are degraded. The paper presents the results of research focused on the use of duplex PVD coatings to increase the life of shaped parts of molds for high-pressure casting of Al and its alloys.

Some feature extraction methods suffer performance degradation in different environments. So it has become a necessity to search for new methods that perform better in different types of conditions. Therefore we can make a comparison of the new found methods to evaluate their performance and to determine which is best in multi-condition tests in order to have e more robust ASR system.

CoO, CuO or NiO supported on Al₂O₃ photocatalysts were prepared by impregnation and then calcination at 400^oC for 3 hours. The obtained samples were physico-chemically studied by Powder X-ray diffraction analysis, X-ray photoelectron spectroscopy and Scanning electron microscopy. The photocatalytic oxidative degradation of aqueous solution of Malachite Green (MG) dye as pollutant using CoO, CuO or NiO supported on Al₂O₃ under UV irradiation was tested. The results determined that the highest degree of degradation of MG dye after 120 minutes was achieved using NiO/ Al₂O₃ photocatalyst (82%) than that the other materials CuO/Al₂O₃ (64%), CoO/Al₂O₃ (59%) and Al₂O₃ (50%). The calculated apparent rate constants increasing in the order: Al₂O₃ (2.7×10^-3 min^-1)<CoO/Al₂O₃ (3.9×10^-3 min^-1)<CuO/Al₂O₃ (4.1×10^-3 min^-1)<NiO/Al₂O₃ (8.4×10^-3 min^-1).

We studied the different parts (lock and feather) of Inconel 738C gas turbine blade, which were cut from the working turbine blade after long operation and recovery heat treatment. Undesired phases such as TCP phase (sigma phase) and some of continuous carbides such as M₂₃C₆ in the grain boundary are found. The presence of M₂₃C₆ carbides in studied samples testifies to the diffusion process of decomposition of MC carbide and the associated softening of the alloy. The appearance of sigma phase leads to embrittlement of the alloy. Generation of these specifications in the structure results in degradation of metallurgical and mechanical properties of the blade and eventually its destruction.