Key Engineering Materials Vol. 822

Abstract: The paper presents the results of an investigation of the influence parameters of laser radiation on the formation of the deposition layer during laser-TIG direct deposition of aluminum wire. Experimental studies have focused on the determination the dependence shape of layer on the laser power, the distance between axis of laser beam and axis of arc, arc parameters. High-speed video recording of the process was carried out. The metallographic analysis of cross-sections of the samples was performed.

Abstract: In comparison with other additive methods, the wire additive manufacturing has some advantages, chief among: high deposition rate and low price for consumables. Otherwise there are some disadvantages such as a high level of internal defects (hot, cold cracks, pores). Adding laser radiation to a WAAM process can significantly reduce data flaws. In this paper outlined research results on the effect of laser radiation (pulsed and permanent) on structure and internal defects of deposit layers to create three-component structures from AlMg6 alloy. Reported samples was made by using hybrid laser-arc method and by applying a single laser. Presented photos of macrosections of obtained samples. Spectral analysis was performed to identify the nature of changes of grains in different processes. Were made the measurements of internal defects and chemical analysis of the obtained walls.

Abstract: The publication describes the results of the research of the influence of laser welding mode parameters on geometry and quality of the formation of the welded joint of 316L steel with thickness of 1 mm. According to the results of research in the framework of pre-project works, in order to test the technology at the real objects, components of light metal structures were welded.

Abstract: Within this work the results of the composition and structural study and mechanical tests of the specimens made from the heat-resistant iron based alloy powder derived from secondary raw material (chips) are presented. The crystalline transformations for the initial condition as well as after several heat treatment conditions were analyzed. Phase and chemical composition were investigated. Mechanical characteristics of the standard flat test bars were defined.

Abstract: Due to the additive manufacturing process concept - layered synthesis of products, it becomes necessary to apply new approaches to the design of parts. One of the main tools that need to operate is numerical simulation, capable, with a skilful approach, to give an engineer an integrated procedure to the development of new products. Numerical modeling, in addition to carrying out strength calculations, includes topology optimization and the creation of lattice structures, through which it is possible to create lightweight products. New design meets requirements of strength characteristics. The use of this tool leads to a reduction in the amount of initial material and as a result - cost saving. In this paper, using the bracket as an example, was used the topology optimization method with subsequent redesign. The paper presents the results of calculations of the stress-strain state of the initial and final structures, allowing estimating the possible reduction in the mass of the product and the amount of consumable material in the manufacture of additive technologies.

Abstract: The relevance of the work is due to the need in the modern world to obtain products with gradient properties for aerospace and medical applications. The method of laser-assisted cold spraying allows obtaining composite materials by additive technology. As a result of this work, a layer of material was constructed from a mechanical mixture of aluminum Al powder with corundum powder Al₂O₃, then the structure and properties of the material obtained were studied, and zones of gradient transition were identified.

Abstract: This paper is devoted to the study of gradient samples of Ti-Ti64 material, manufactured by selective laser melting. The measurements of porosity, differences in densities are made with x-ray computed tomography for as-processed and after hot isostatic pressing samples. The raw data was processed using the software Volume Graphics and AVIZO. The porosity of the samples was studied and their sphericity was calculated.

Abstract: This work investigates the Selective Laser Melting (SLM) process for the in-situ synthesis of Ti-5Al and Ti-6Al-4V alloys using elemental powder mixture. Elemental spherical powders were used to prepare a powder mixture and then samples were produced by SLM using different volume energy density. The effects of volume energy density during SLM on samples’ relative density, chemical composition, microstructure and microhardness before and after heat treatment have been studied. It was shown that volume energy density during the SLM process significantly effects the density, microstructure of Ti-5Al and Ti-6Al-4V alloys, as well as, the microhardness of Ti-6Al-4V obtained from elemental powders.

Abstract: The Nb-Si in-situ composite samples were fabricated by laser metal deposition additive manufacturing technology from mechanically alloyed powders in vario-planetary ball mill. A laser metal of samples was carried out at various laser powers: 500 W, 1000 W, 1400 W. The microstructure of a sample grown at a laser power of 500 W consists of a solid solution of Nb, Nb₃Si, and dendritic chains of Ti. When the laser power is increased to 1000 W, the volume fraction of silicides increases, the structural heterogeneity decreases. With further increase in laser power to 1400 W, Ti dissolves in Nb, dendritic chains disappear, Nb₅Si₃ silicide stabilizes.

Abstract: The article presents the results of a study on the additive manufacturing of functional graded steel parts. Studies have been carried out on the possibility of growing blanks from two steels simultaneously – tool steel H13 and stainless steel 316L. The study of the microstructure of the transition from one steel to another showed that the transition layer is smooth and is about 200 microns thick. The mechanical properties in the transition layer are distributed over the gradient and smoothly change from one material to another. The structure and properties of the transition layer after heat treatment and hot isostatic pressing are shown.