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

This paper aims to study the reinforcement effects of alumina (23) particles on the mechanical properties of base alloy melt of (6061). The samples of metallic composites with dispersed particles percentage (5%, 10% and 15%) are prepared by casting vortex method, which help the particles entrance in the matrix and distribution of it in homogeneous form. The purpose of this study is to improve the hardness, impact strength, tensile strength, and compressive strength, which are increased with the increment of the added particle’s amount due to the hardness of alumina particles. Based on the results it concluded that the value of the durability increases with the increase in the percentages of the particles by weight between three stages. Also, the addition of aluminum oxide particles increased the tensile resistance and thus improved the mechanical properties of the base material. It was also noted that with the addition of aluminum oxide, the melting point of the metal increased and reached about 980 degrees Celsius.

The paper presents the results of testing the joints of unequal materials using flow-drill technology and a combination of flow-drill technology and adhesive bonding. The formed joints were tested by tensile and shear test according to ISO 12996. The positive effect of adhesive bonding on the load-bearing capacity of the joints and on the stress distribution in the tested materials was observed.

Three-dimensional (3D) printing technologies have been developed for prototype purposes. However, it has become possible to manufacture various functional parts with improving mechanical properties of 3D printing materials. Although polylactic acid (PLA) is the most widely used 3D printing material, the mechanical properties required for functional parts are not sufficient. For this reason, carbon fibre reinforced PLA composites are preferred as 3D printing material to advance the mechanical properties of the fabricated parts. However, for 3D printed parts, it is known that the layer thickness and printing orientation angles affect the mechanical properties. In this study, unreinforced PLA and 15% carbon fibre reinforced PLA composite tensile specimens were 3D printed using fused deposition modeling (FDM) technique. The effects of printing orientation angle and layer thickness on modulus of elasticity and tensile strength are investigated. 3D printed unreinforced PLA samples exhibited better tensile performance as compared to carbon fibre reinforced PLA composite samples.

Technique and equipment for plasma spraying of wear-resistant and corrosion-resistant coatings with enhanced adhesive strength was developed. Ceramic powders coated metal thin films were used for plasma spraying. Optimal conditions for deposition of the metal films on the particles of alumina powder (40…63µm fraction) by PVD process were obtained. Deposition of two- layer films on the powder particles was carried out. The first layer was titanium and the second layer was aluminum or copper. The titanium as adhesively-active element capable of wet alumina is necessary for increase the adhesion strength vacuum films as well as plasma sprayed coatings.

A special plasma-spray gun with external arc working in a mode of laminar plasma argon jet generation was designed. Such regime provides melting of the refractory ceramic core, saving metal films as well as localization of thermal effects during spraying process.
The results of testing coated specimens confirmed that the developed technique improves the physical and mechanical properties of the plasma sprayed composite coatings. The sprayed composite coatings were compared with coatings sprayed using pure alumina powders in terms of adhesion, wear and corrosion properties. The shear adhesion strength increases up to about 1.9 times, the wear resistance increases about 5 to 7 times, the corrosion resistance increases about 2.5 to 5 times.

The shear adhesion strength was measured at tension of coated specimen at room temperature by developed adhesion testing technique. The substrate was flat and dog-bone-shaped. The substrate with rectangular cross-section was partially coated with plasma- sprayed coating. The specimens were tested in uniaxial tension under displacement control. The tensile specimens were loaded to adhesion delamination of the coating. Sprayed coating was detached as a result of shear interface stresses.