Sergey Dmitrievich Neulybin

This article presents the results of plasma surfacing of VT6 titanium alloy using reciprocating feed of 3- and 5-mm-diameter filler wires. Key aspects of u

The art icle is devoted to the development of technologies for the additive manufacturing of metal products including aluminum alloys. In recent years, additive technologies have made significant progress in improving the methods of applying the material, however, the task of reducing costs in 3D printing remains urgent. One of the ways to solve this problem may be to ensure minimum allowances before finishing surfaces, especially for aluminum alloys, which have increased roughness during WAAM printing due to limited surface wettability because of the presence of an oxide film. A study has been conducted on the possibility of improving the surface quality of a prototype made of aluminum alloy 4047, obtained by arc surfacing with a melting electrode. A method of additional exposure is proposed immediately after surfacing the prototype by sealing the workpiece side surface using a direct-acting plasma arc of reverse current polarity. The microstructure has been evaluated before and after the surface melting. It is shown that the application of a special treatment mode does not harm the microstructure. Using 3D scanning, it has been found that the surface of the prototype after plasma arc melting becomes smoother compared to the initial state, which ultimately reduces surface roughness by up to 2 times and reduces the cost of finishing mechanical treatment.The research was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation within the framework of the state assignment “Development of scientific and technological foundations for the formation of a material-structure system with special properties based on hybrid additive technologies” No. FSNM-2024-0003.

Inter-pass forging with different degrees of deformation during WAAM of Inconel 718 specimens (single-stage, three passes; two-stage, six passes) was investigated. Macrostructural analysis of the specimens showed that inter-pass forging led to a recrystallized structure. Alternation of layers with different grain shapes (columnar and equiaxed) is observed throughout the height of the specimens. Increasing the number of passes improves the mechanical properties of the material (tensile strength, yield strength, microhardness). A finite element model of inter-pass forging was developed to determine the effect of inter-pass surface deformation during WAAM on the residual stress–strain state. The non-stationary formulation was replaced with a quasi-static one. Johnson–Cook material constants were obtained for the deposited Inconel 718 material, including the effect of forging. Verification of the mathematical model was performed using a wall (specimen 2) deposited with single-stage forging. The deviation between the simulation results and the experiment did not exceed 15%. It was found that the sequence and number of passes significantly affect residual strain and displacements but have little effect on residual stress. Numerical modeling showed that the depth of plastic deformation exceeds the melting depth when depositing the subsequent layer, ensuring the preservation and accumulation of the inter-pass forging effect throughout the deposition process.

The development of new technologies for manufacturing products from magnesium alloys, with the aim to achieve high performance characteristics at reduced p

The problem of improving the quality of metal materials during additive manufacturing of workpieces is a relevant one. Additive technologies based on melti

Using keyhole plasma arc welding, welded joints of a Ti₂AlNb-based alloy, VTI-4, were obtained, and their structure and mechanical properties were studied. It has been established that the dynamic effect of a keyhole arc had a positive effect on the quality of the welded joint; namely, lack of penetration, porosity, and microcracks were eliminated. The welded joint consisted of a fusion zone (FZ), a heat-affected zone (HAZ), and a base metal (BM). Depending on the phase composition and morphology of the obtained phases, the HAZ can be divided into four zones: HAZ1 with large β-phase grains near the melting line, HAZ2 with large β-phase grains + α₂, HAZ3 with more fragmented β-phase grains retaining more α₂-phase, and HAZ4 with the phase composition β + α₂ + O. Subsequent heat treatment (HT: quenching at 920 °C for 2 h, cooling in air, followed by aging at 800 °C for 6 h, cooling in air) preserved the zone structure of the weld but led to the formation of the O-phase within β-grains. The microhardness of the weld in the zone corresponds to 360±15 HV0.2, but after HT, it increased to 382±20 HV0.2. The strength properties of the welded joint after HT were above 90 % of the base metal (σ_ucs = 1120 MPa, σ_0.2 = 1090 MPa), while elongation to failure is close to the initial condition (δ = 2.1 %).

This work presents the results of testing the plasma hardfacing of bronze on steel with the help of a plasmatron used at positive and reverse polarities. M