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High-strain deformation and spallation strength of 09crni2mocu steel obtained by direct laser deposition

Klimova-Korsmik, O., Turichin, G., Mendagaliyev, R., Razorenov, S., Garkushin, G., Savinykh, A., Korsmik, R.

(2021) Metals, 11 (8), статья № 1305.


КРАТКОЕ ОПИСАНИЕ: In this work, the critical fracture stresses during spalling of high-strength steel 09CrNi2MoCu samples obtained by direct laser deposition (DLD) were measured under shock compression of up to ~5.5 GPa. The microstructure and mechanical properties of DLD steel samples in the initial state and after heat treatment were studied and compared to traditional hot rolled one. The microstructural features of steel before and after heat treatment were revealed. The heat treatment modes of the deposit specimens on their strength properties under both static and dynamic loads have been investigated. The spall strength of the deposited specimens is somewhat lower than the strength of steel specimens after hot rolling regardless of their heat treatment. The minimum elastic limit of elasticity is exhibited by the deposit specimens. After heat treatment of the deposit samples, the elastic limit increases and approximately doubles. Subsequent heat treatment in the form of hardening and tempering allows obtaining strength properties under Hugoniot loads in traditional hot-rolled products.

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Computer simulation of hydrodynamic and thermal processes in DLD technology

Turichin, G.A., Valdaytseva, E.A., Stankevich, S.L., Udin, I.N.

(2021) Materials, 14 (15), статья № 4141.


КРАТКОЕ ОПИСАНИЕ: This article deals with the theoretical issues of the formation of a melt pool during the process of direct laser deposition. The shape and size of the pool depends on many parameters, such as the speed and power of the process, the optical and physical properties of the material, and the powder consumption. On the other hand, the influence of the physical processes occurring in the material on one another is significant: For instance, the heating of the powder and the substrate by laser radiation, or the formation of the free surface of the melt, taking into account the Marangoni effect. This paper proposes a model for determining the size of the melt bath, developed in a onedimensional approximation of the boundary layer flow. The dimensions and profile of the surface and bottom of the melt pool are obtained by solving the problem of convective heat transfer. The influence of the residual temperature from the previous track, as well as the heat from the heated powder of the gas–powder jet, taking into account its spatial distribution, is considered. The simulation of the size and shape of the melt pool, as well as its free surface profile for different alloys, is performed with 316 L steel, Inconel 718 nickel alloy, and VT6 titanium alloy.

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Features of heat treatment the ti-6al-4v gtd blades manufactured by dld additive technology

Gushchina, M., Turichin, G., Klimova-Korsmik, O., Babkin, K., Maggeramova, L.

(2021) Materials, 14 (15), статья № 4159.


КРАТКОЕ ОПИСАНИЕ: Additive manufacturing of titanium alloys is one of the fastest growing areas of 3D metal printing. The use of AM methods for parts production in the aviation industry is especially promising. During the deposition of products with differently sized cross-sections, the thermal history changes, which leads to non-uniformity of the structure and properties. Such heterogeneity can lead to failure of the product during operation. The structure of deposited parts, depending on the thermal cycle, may consist of α’, α + α’ + β’, and α + β in different ratios. This problem can be solved by using heat treatment (HT). This paper presents research aimed towards the determination of optimal heat treatment parameters that allows the reception of the uniform formation of properties in the aftertreatment state, regardless of the initial structure and properties, using the example of a deposited Ti-6Al-4V gas turbine blade.

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Analytical solution of the non-stationary heat conduction problem in thin-walled products during the additive manufacturing process

Mukin, D., Valdaytseva, E., Turichin, G.

(2021) Materials, 14 (14), статья № 4049.


КРАТКОЕ ОПИСАНИЕ: The work is devoted to the development of a model for calculating transient quasiperiodic temperature fields arising in the direct deposition process of thin walls with various configurations. The model allows calculating the temperature field, thermal cycles, temperature gradients, and the cooling rate in the wall during the direct deposition process at any time. The temperature field in the deposited wall is determined based on the analytical solution of the non-stationary heat conduction equation for a moving heat source, taking into account heat transfer to the environment. Heat accumulation and temperature change are calculated based on the superposition principle of transient temperature fields resulting from the heat source action at each pass. The proposed method for calculating temperature fields describes the heat-transfer process and heat accumulation in the wall with satisfactory accuracy. This was confirmed by comparisons with experimental thermocouple data. It takes into account the size of the wall and the substrate, the change in power from layer to layer, the pause time between passes, and the heat-source trajectory. In addition, this calculation method is easy to adapt to various additive manufacturing processes that use both laser and arc heat sources.

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Effect of Scanning Strategy on Mechanical Properties of Ti-6Al-4V Alloy Manufactured by Laser Direct Energy Deposition

Gushchina, M.O., Kuzminova, Y.O., Kudryavtsev, E.A., Babkin, K.D., Andreeva, V.D., Evlashin, S.A., Zemlyakov, E.V.

(2021) Journal of Materials Engineering and Performance.


КРАТКОЕ ОПИСАНИЕ: Direct energy deposition (DED) is an additive manufacturing method that allows repairing the broken parts and building the meter-scale samples. However, the printing of large parts is associated with huge residual stresses and martensite phase formation, which can change the geometry of final samples or initiate the crack. The last factor is especially important for titanium alloys. In this work, we investigated the effect of DED thermal history on the obtained structural and mechanical properties of Ti-6Al-4V using a thermocouple. It was demonstrated that printing with long pauses leads to α′ phase formation, which embrittles the material. Continuous printing with small pauses between tracks leads to the formation of the dual α+β structure. The effect of the texture on the material properties is also discussed. As a result of the study, the specific DED process parameters allow the same mechanical characteristics for as-built titanium alloy and the alloy after heat treatment.

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Studying the layer structure formation in laser additive manufacturing with AlMg6 alloy wire

Eremeev, A.D., Tsibulskiy, I.A., Akhmetov, A.D., Mukin, D.V., Davletshin, A.O.

(2021) Journal of Physics: Conference Series, 1891 (1), статья № 012034.


КРАТКОЕ ОПИСАНИЕ: When processing aluminum alloys with repeated laser radiation, which is typical for both multi-pass welding and additive manufacturing, volatile chemical components are being burnt. Due to the processing zone overheating if there are residual stresses, the probability of there being structural defects and deformations and, consequently, distortion of the final shape of the sample increases. Studies of the wall's structure forming process during laser additive manufacturing with AlMg6 alloy wire, fulfilled based on experiments and computational methods, allowed us to obtain the necessary data for optimizing the process and determining the laser treatment modes. The simulation of the thermocyclic effect of laser radiation on the wall and the selection of mode parameters for the optimal structure of the material and the shape of the bead were performed. The results for the chemical composition of the final material, the number of defects and mechanical properties were quite satisfactory.

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Effect of Temperature Field on Mechanical Properties of Direct Laser Deposited Ti-6Al-4V Alloy

Gushchina, M.O., Yu Ivanov, S., Vildanov, A.M.

(2020) IOP Conference Series: Materials Science and Engineering, 969 (1), статья № 012103.


КРАТКОЕ ОПИСАНИЕ: The mechanical and service properties of Ti-6Al-4V alloy parts produced by direct laser deposition (DLD) depend on the thermal cycle parameters. The temperature field during deposition is significantly affected not only by the parameters of the process, but also by the interpass dwell time and length of the deposited layers. The aim of the article is to establish the relationship between mechanical properties of deposited Ti-6Al-4V samples and DLD thermal cycle parameters. Numerical simulation was used in order to establish relationship between temperature field parameter and the process parameters. The nonlinear three-dimensional heat conduction problem was solved by the finite element method. It is shown that an increase in the dwell time between passes from 5 to 10 seconds leads to a significant decrease in the inter-pass temperature and an increase in the cooling rate. This leads to the metastable structure formation of the deposited layers of Ti-6Al-4V that consists mainly of a nonequilibrium a'-phase which hardness is higher than 390 HV. Without dwell time an equilibrium a + (3 structure with hardness of 360 HV and higher elongation is formed.

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Heat treatment of corrosion resistant steel for water propellers fabricated by direct laser deposition

Mendagaliev, R., Klimova-Korsmik, O., Promakhov, V., Schulz, N., Zhukov, A., Klimenko, V., Olisov, A.

(2020) Materials, 13 (12), статья № 2738, pp. 1-9.


КРАТКОЕ ОПИСАНИЕ: The urgency of heat treatment of samples of maraging steel obtained by direct laser deposition from steel powder 06Cr15Ni4CuMo is considered. The structural features and properties of 06Cr15Ni4CuMo steel samples after direct laser deposition and heat treatment are studied. The work is devoted to research into the influence of thermal processing on the formation of structure and the mechanical properties of deposit samples. Features of formation of microstructural components by means of optical microscopy are investigated. Tests for tension and impact toughness are conducted. As a result, it was established that the material obtained by the direct laser deposition method in its initial state significantly exceeds the strength characteristics of heat treatment castings of similar chemical composition, but is inferior to it in terms of impact toughness and relative elongation. The increase in relative elongation and impact toughness up to the level of cast material in the deposit samples is achieved at the subsequent heat treatment, which leads to the formation of the structure of tempered martensite and reduction in its content at two-stage tempering in the structure of the metal. The strength of the material is also reduced to the level of cast metal.

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The approaches to design and manufacturing of large-sized marine machinery parts by direct laser deposition

Korsmik, R., Tsybulskiy, I., Rodionov, A., Klimova-Korsmik, O., Gogolukhina, M., Ivanov, S., Zadykyan, G., Mendagaliev, R.

(2020) Procedia CIRP, 94, pp. 298-303.


КРАТКОЕ ОПИСАНИЕ: This article shows several aspects of additive manufacturing via direct laser deposition of machinery parts. The redesigning methods of product manufactured by conventional technologies are considered, taking into account the stress-strain state of a sample manufactured by the DLD-method. Besides modeling methods allow obtaining a product of required geometry, the experience of applying the topological optimization method of structure is demonstrated. The product with optimized design has reliability characteristics close to the original solid version. The differences in the product microstructure obtained by the DLD-method from the structure after casting and thermomechanical processing are shown. The mechanical properties of built-up material are comparable to the same properties after casting and rolling. Economic evaluation of DLD introduction was held. A criterion of advisability replacement to DLD-method of manufacturing is determined. The results prove attractiveness of digital laser technologies application in shipbuilding.

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Investigation of cracking causes during multi-pass laser cladding of heat-resistant single crystal nickel alloy

Korsmik, R., Klimova-Korsmik, O., Valdaytseva, E., Udin, I.

(2020) Procedia CIRP, 94, pp. 314-319.


КРАТКОЕ ОПИСАНИЕ: ZhS32 is Ni-based single crystal superalloy has been successfully used in aero and industrial gas turbine applications. Vibrations, shocks, abrasive wear, high temperatures applied to gas turbine blades lead to its damage. Taking into account the complexity of production and the high cost of new blades, after the exploitation of their resource, the blades must be restored. Laser cladding, as one type of DED process, is applicable to repairing operation for machines and mechanisms are subjected to the impact of aggressive environment and surface wear. superalloys with a high γ'-volume fraction are strongly susceptible to crack formation, e.g., strain age or liquidation cracking. The influence of main cladding parameters on the potential defects of deposited metal is considered. Based on the obtained dependencies, the criteria allow obtaining a defect-free clad with controlled structure are determined. As result of investigation, a technological recommendations for restoration laser powder cladding of turbine blades from heat-resistant nickel alloys is developed.

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Development of laser metal deposition process for a large IN625 part using small trial samples

Artur, V., Konstantin, B., Anton, K., Andrey, A., Marina, G.

(2020) Procedia CIRP, 94, pp. 310-313.


КРАТКОЕ ОПИСАНИЕ: The laser metal deposition process is characterized by multiple reheating with high heating and cooling rates, which vary during the deposition process and depend on the size and shape of the part. The development of the process parameters is an essential step in preparing for manufacturing of the real part. As a rule, small trial samples are used for this purpose. Difference in the temperature field during deposition of samples and real part leads to the different microstructure, properties and macrodefects. The aim of this work is to approximate the thermal histories of trial samples and real parts by varying process parameters. It was shown that by varying dwell time and interpass temperature it is possible to obtain similar thermal histories. Metallographic studies showed the absence of defects, the same microstructure and mechanical properties (microhardness) of the samples and real part.

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Distortion prediction and compensation in direct laser deposition of large axisymmetric Ti-6Al-4V part

Babkin, K., Zemlyakov, E., Ivanov, S., Vildanov, A., Topalov, I., Turichin, G.

(2020) Procedia CIRP, 94, pp. 357-361.


КРАТКОЕ ОПИСАНИЕ: A Ti-6Al-4V alloy aircraft engine part consisting of a cylinder (inner radius 977 mm, height 250 mm and 7.5 mm wall thickness) and two flanges (10.5 and 13.5 mm thick) was manufactured by direct laser deposition technology. A two-dimensional thermomechanical model was developed to simulate distortion of large axisymmetric parts during direct laser deposition. As it was established the shape and dimensions of the finished part, simulated using the original CAD model, have unacceptable deviations from the required parameters. A significant correction of the model is necessary to ensure the required accuracy. It was found that for complete compensation of deformations, an initial geometry should be pre-distorted according to the inverted distortions predicted by the FE simulation. To prevent fracture of the build-up, an 8 mm thick flexible substrate was used. The DLD process stability was ensured by taking into account spatial position of the deposited part in the motion path of the processing head. The simulated shape and size of the finished part satisfactory agrees with the experimentally obtained.

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Comparative analysis of the gamma prime phase formation in nickel alloys in additive manufacturing

Turichin, G.A., Klimova-Korsmik, O.G., Valdaytseva, E.A., Alekseev, A.V., Rashkovets, M.V.

(2020) Procedia CIRP, 94, pp. 320-323.


КРАТКОЕ ОПИСАНИЕ: The mechanical properties of Ni-based superalloys are based on the hardening gamma-prime phase with an ordered structure. A solution for new phase precipitate growth is suggested for the case of the Ni-based alloys. In accordance with solution a mathematical model of gamma-prime phase precipitates growth during direct laser deposition, which is a type of DED-method, was developed in order to be able to predict the size of the hardening gamma-prime phase grains and thus the mechanical properties of the alloy. A series of experiments on depositing samples using Ni-based superalloys powder was carried out to verify this model.

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Formation of bead shape, structure and mechanical properties of coldresistant high-strength steel produced by direct laser deposition method

Zadykyan, G.G., Korsmik, R.S., Mendagaliev, R.V., Turichin, G.A.

(2020) Solid State Phenomena, 299 SSP, pp. 345-350.


КРАТКОЕ ОПИСАНИЕ: The technology of direct laser deposition is the most promising for use in various industries. One of the most interesting industries for using this technology is shipbuilding. Due to its unique properties, cold-resistant steels are widely used in shipbuilding for brackets of mushroom propellers, stems, and also structures for work on the Arctic shelf. In this paper, the studies of the influence of technological parameters on the formation of the geometry and properties of products are represented. The technological parameters of the process of direct laser deposition parts from steel 0909CrNi2MoCu are determined.

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Nitriding of steels of various structural classes manufactured by laser additive technologies

Tsvetkova, E.V., Bazaleeva, K.O., Chekin, I.S., Klimova-Korsmik, O.G., Zhidkov, A.S.

(2020) Izvestiya Ferrous Metallurgy, 63 (1), pp. 63-70.


КРАТКОЕ ОПИСАНИЕ: The authors have conducted a comparative analysis of diffusion layers of steels of various structural classes manufactured by complex technology including laser remelting of powder material and plasma nitriding. Parameters of diffusion layers of bainitic steel (Fe - 0.09 % C - 1 % Cr - 2 % Ni - 1 % Mo - 1 % Cu) and martensitic steel (Fe-0.25 % C - 13 % Cr-2 % Ni) manufactured by direct laser deposition (DLD) and austenitic steel (Fe-0.03 % C-17 % Cr-14 % Ni-3 % Mo) manufactured by selective laser melting (SLM) were investigated. During plasma nitriding at 540 °C for 24 h of martensitic and austenitic steels, diffusion layer of 140-160 μm was formed, additionally maximum microhardness of surface layer was 800 HV0.1 and 1050 HV0.1 and it is almost constant on thickness of 100 μm. Diffusing layer of bainitic steel is 900 μm and its microhardness monotonously decreases from the surface. Reinforcing phases of nitrided layer were determined by X-ray analysis: γ' (Fe4N) is fixed in the bainitic steel, γ' and CrN are fixed in martensitic and austenitic steels. Moreover on the surface of austenitic steel solid nitrided layer is formed. The influence of heat treatment after laser remelting of powder material was also studied. It was determined, that despite decreasing of crystal structure defects after heat treatment, the thickness of nitrided layer changes slightly. Also the authors have investigated the influence of porosity of austenitic steel on the thickness of nitrided layer. It was shown, that porosity of 0.5-2.0 % doesn't result in changing of diffusion layer's thickness.

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Stress distribution in laser metal deposited multi-layer thick-walled parts of Ti-6Al-4V

Ivanov, S., Zemlyakov, E., Babkin, K., Turichin, G., Karpov, I., Em, V., Rylov, S.

(2019) Procedia Manufacturing, 36, pp. 240-248.


КРАТКОЕ ОПИСАНИЕ: The laser metal deposition is an additive manufacturing technology enabling the production of large scale complex parts without additional treatment like welding or machining. The study of the origin of the stress field during laser metal deposition is essential for solving a number of problems, including: the assessment of cold and hot cracking; prediction of the fatigue resistance, and stress corrosion cracking. The quantitative study of transient and residual stresses in build parts is necessary for optimising the parameters of processing and post-production stress relieving heat treatment. Residual stress field in laser metal deposited 50-layer (4-pass per layer) wall of Ti-6Al-4V was analysed experimentally using neutron diffraction and numerically using finite element simulation. Long dwell time between passes and a rigid substrate was used in order to simulate conditions of large scale parts fabrication. An analysis of the calculated and experimentally measured residual stress field showed that near the edges of the buildup there is a region where all three components of stress field are tensile, and normal stress exceeds the yield stress by more than 25%. Moreover, normal plastic strain in this area are also tensile and reaches 2.5-3%. The longitudinal tensile stress closes to yield stress on almost the entire length of the several last layers near the top of the buildup. Residual stress field calculated using neutron diffraction data according to interplanar lattice distance obtained assuming plane stress approach has a satisfactory agreement with FE simulated results.

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Microstructure and mechanical properties of laser metal deposited cold-resistant steel for arctic application

Mendagaliyev, R., Turichin, G.A., Klimova-Korsmik, O.G., Zotov, O.G., Eremeev, A.D.

(2019) Procedia Manufacturing, 36, pp. 249-255.


КРАТКОЕ ОПИСАНИЕ: The article presents the study of the direct laser deposition (DLD) process of cold-resistant steel 09CrNi2MoCu (F620W). As a result, many bainite transformation products are produced. The formation of a bainitic structure in the process of deposition is still little studied; in the process of the growth of the deposited wall, the microstructure undergoes a phase transformation. The work details the equipment for direct laser deposition, describes the main technological parameters of the regime, and studies the surface of the steel powder. Mechanical tests for impact toughness were carried out at a temperature of .40°N, with different laser emission powers. The results are given using the initial powder, as well as used powder with a different mixing ratio, and the results are analyzed. As a result of the study, it was established that the fractional composition of the F620W alloy powder has a significant effect on the mechanical characteristics of samples obtained by direct laser deposition. The effect of recycled powder on the mechanical properties of the samples obtained is given.

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Research of technological possibility of increasing erosion resistance rotor blade using laser cladding

Kuznetsov, M., Turichin, G., Silevich, V., Ochkasov, V., Sorokin, A.

(2019) Procedia Manufacturing, 36, pp. 163-175.


КРАТКОЕ ОПИСАНИЕ: The publication describes the results of the research of the influence of the parameters of the mode of a laser deposition on the metallurgy of deposited layers, mechanical characteristics and deformations of the samples. Plates, which had made of PC E36 steel and 15Cr11MoW steel, were used as samples. According to the results of experimental researches the peripheral areas of the input edges of the blades were made. Also, an experimental research was conducted on how the parameters of the mode and trajectory of the deposition influence on mechanical and operational characteristics, as well as the deformations forming in the product during the laser surfacing of the Stellite 6 alloy influence on the heat-resistant high-alloy steel 15Cr11MoW.

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Inconel 625/TiB2 metal matrix composites by direct laser deposition

Promakhov, V., Zhukov, A., Ziatdinov, M., Zhukov, I., Schulz, N., Kovalchuk, S., Dubkova, Y., Korsmik, R., Klimova-Korsmik, O., Turichin, G., Perminov, A.

Metals 2019, 9(2), 141


КРАТКОЕ ОПИСАНИЕ: This work presents results in the field of synthesis of new metal matrix composites with matrix NiTi and particles TiB2, and their use as additives to fabricate metal matrix composites based on the Inconel 625 alloy. NiTi-TB2 powders were obtained using self-propagating high-temperature synthesis. Composite NiTi-TiB2 particles were spheroidized on a high-frequency induction plasmatron. Composite NiTi-TB2 particles were mixed with metallic Inconel 625 powder with particle sizes of 50–150 µm. We used direct laser deposition by means of mixture of powders to grow samples with different contents of ceramics in the metal matrix. The process of direct laser deposition during the experiment was investigated. We have determined the peculiarities of the formation of the structure in metal matrix composites with different contents of titanium diboride. We have demonstrated the possibility of using Direct Laser Deposition (DLD) for fabricating items from ceramic metal materials. We have determined promising fields of further research for the purpose of obtaining efficient metal matrix composites using additive manufacturing technologies.

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Research of the treatment parameters effects on the layer formation during wire-feed laser-TIG deposition with aluminum alloy

Somonov, V.V., Tsibulskiy, I.A., Kislov, N.G., Lanin, A.A.

(2019) Key Engineering Materials, 822, pp. 496-503.


КРАТКОЕ ОПИСАНИЕ: 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.