Research

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11 pages, 7716 KiB

Open AccessArticle

Microstructural Evolution and Mechanical Behavior of TA15 Titanium Alloy Fabricated by Selective Laser Melting: Influence of Solution Treatment and Aging

by Qing Wang, Binquan Jin, Lizhong Zhao, Xiaolian Liu, Anjian Pan, Xuefeng Ding, Wei Gao, Yufeng Song and Xuefeng Zhang

Metals 2023, 13(9), 1514; https://doi.org/10.3390/met13091514 - 24 Aug 2023

Viewed by 911

Abstract

In this study, TA15 titanium alloys were successfully prepared using selective laser melting (SLM). The results show that the microstructure of each TA15 specimen is composed of a large number of acicular α’ martensite crystals accompanied by a lot of dislocations and twin [...] Read more.

In this study, TA15 titanium alloys were successfully prepared using selective laser melting (SLM). The results show that the microstructure of each TA15 specimen is composed of a large number of acicular α’ martensite crystals accompanied by a lot of dislocations and twin structures in the martensite due to non-equilibrium heating and cooling via SLM. After solution treatment and aging treatment, the martensite structure is successfully transformed into a typical duplex structure and an equiaxial structure. When there is an increase in the solution temperature, the size of the equiaxed primary α phase and the elongation of the specimen gradually increases, while the thickness of the layered secondary α phase and the tensile strength of the specimen decreases accordingly. After solution treatment at 1000 °C, the specimens show the best comprehensive mechanical properties, i.e., a high-temperature tensile strength of 715 MPa and a corresponding elongation of 24.5%. Subsequently, an appropriate solution–aging treatment is proposed to improve the high-temperature mechanical properties of SLMed TA15 titanium alloys in aerospace. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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16 pages, 9176 KiB

Open AccessArticle

Aluminum Bronze Crystallization on Deformed Base during Electron Beam Additive Manufacturing

by Anton Y. Nikonov, Dmitry V. Lychagin, Artem A. Bibko and Olga S. Novitskaya

Metals 2023, 13(6), 1012; https://doi.org/10.3390/met13061012 - 24 May 2023

Cited by 1 | Viewed by 1028

Abstract

To obtain products by using additive manufacturing (AM) methods, it is necessary to take into account the features of the formed internal structure of the material. The internal structure depends on the 3D printing parameters. To predict it, it is effective to use [...] Read more.

To obtain products by using additive manufacturing (AM) methods, it is necessary to take into account the features of the formed internal structure of the material. The internal structure depends on the 3D printing parameters. To predict it, it is effective to use computer modeling methods. For this purpose, using the example of aluminum bronze, the influence of the base structure and heat input during surfacing on the grain structure of the deposited layers was studied. To create numerical models, we used data obtained from electron backscatter diffraction (EBSD) analysis of samples. The heterogeneity of the formation of the structure in each selected zone is established, which indicates the heterogeneity of heat input in local areas of the material in one mode of surfacing. For typical cases of crystallization, modeling using the molecular dynamics (MD) method of crystallization processes with different heat inputs to the base with characteristics specified based on experimental data was carried out. It was established that the amount of heat input determines the degree of melting and the inherited defectiveness of growing crystals. The formation of misorientation boundaries and crystallization centers of new grains is determined by the conditions of joint growth of grains with given crystallographic parameters of the computational model. The grain structure obtained as a result of simulation is consistent with the experimentally observed structure of the samples. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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15 pages, 5247 KiB

Open AccessArticle

Novel Approach to Prepare Magnesium and Mg-Al Alloy from Magnesia by Using the Closed Microwave Aluminothermic Method

by Teng Zhang, Miao Wang, Libin Niu, Jumei Zhang, Huihui Zhang and Mengchun Zhang

Metals 2023, 13(5), 905; https://doi.org/10.3390/met13050905 - 07 May 2023

Viewed by 1213

Abstract

Herein, we report a novel approach to obtaining magnesium and nanocrystal Mg-Al alloy from magnesia using a closed microwave aluminothermic method in order to solve the problems of high energy consumption, high pollution, and low productivity in the process of magnesium and its [...] Read more.

Herein, we report a novel approach to obtaining magnesium and nanocrystal Mg-Al alloy from magnesia using a closed microwave aluminothermic method in order to solve the problems of high energy consumption, high pollution, and low productivity in the process of magnesium and its alloy production. The main idea of the paper is to design a technique for the preparation of magnesium–aluminum alloy during the reduction process of MgO directly under atmospheric pressure. Based on this experimental idea, we have established a closed microwave aluminothermic reduction reactor. The great advantage of the reaction device is that it can make the reaction material heat up quickly to the reaction temperature in the microwave heating process and produce high-pressure magnesium vapor, which reacts with aluminum dramatically to form Mg-Al alloy under microwave irradiation. By the calculation of the electromagnetic field of the reaction device and sample using ANSYS electronics desktop 2018, the optimum microwave heating conditions for samples have been established. Based on the calculation results, we demonstrate that magnesium and its alloy are prepared successfully by using this method. In addition, the reduction rate of MgO is greatly improved, which is higher up to 79.97 Wt% when the reduction time is 30 min, at 1273 K, and the Mg₂Al₃ and MgAl alloy is formed during the reduction process as well. Moreover, the formation mechanism of Mg-Al alloy during the reduction process under microwave irradiation was discussed further. Our findings could provide a new approach, insights, and research directions to obtain magnesium and Mg-Al alloy directly from magnesia under normal pressure. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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14 pages, 5086 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Cu-11Al-5Ni-4Fe wt% Manufactured by LPBF

by Carolina Guerra, Jorge A. Ramos-Grez, Iván La Fé-Perdomo, Alejandro Castillo and Magdalena Walczak

Metals 2023, 13(3), 459; https://doi.org/10.3390/met13030459 - 22 Feb 2023

Viewed by 1357

Abstract

Cu-11Al-5Ni-4Fe wt% alloy is processed by additive manufacturing using the laser powder bed fusion (LPBF) technique in two building orientations (90° and 0° to the building platform) to determine which laser parameters are more critical to obtain better mechanical properties. The resulting printed [...] Read more.

Cu-11Al-5Ni-4Fe wt% alloy is processed by additive manufacturing using the laser powder bed fusion (LPBF) technique in two building orientations (90° and 0° to the building platform) to determine which laser parameters are more critical to obtain better mechanical properties. The resulting printed material is characterized microstructurally and mechanically by XRD, optical microscope, and under compressive stress. The results indicate that the alloy achieved good densification and mechanical properties similar to an as-cast counterpart. The as-built microstructure comprises acicular martensite and other thermodynamic equilibrium phases, while exothermic and endothermic curves show a poor response to temperature induce phase transformation at ~350 °C. The mechanical results show that it is possible to reach a compressive strength of 1300 MPa, up to 20% strain, and better mechanical properties in those samples fabricated in a vertical direction (90°) than the horizontal. The volumetric energy density also affects the samples’ maximum strength and superficial roughness. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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11 pages, 4525 KiB

Open AccessArticle

Selective Laser Melting of Inconel 718/TiC Composite: Effect of TiC Particle Size

by Vadim Sufiiarov, Danil Erutin, Evgenii Borisov and Anatoly Popovich

Metals 2022, 12(10), 1729; https://doi.org/10.3390/met12101729 - 15 Oct 2022

Cited by 7 | Viewed by 1647

Abstract

In this article, we present the results of a study of the effect of TiC particle size on the microstructure and properties of a composite material based on the heat-resistant nickel alloy Inconel 718. Composite materials with the addition of 1% mass of [...] Read more.

In this article, we present the results of a study of the effect of TiC particle size on the microstructure and properties of a composite material based on the heat-resistant nickel alloy Inconel 718. Composite materials with the addition of 1% mass of micron- or nano-sized TiC particles were successfully manufactured by selective laser melting. Hot isostatic pressing and heat treatment were applied to manufactured samples. Increasing hardness with the addition of TiC particles by about 20% without dependence on TiC size was determined. The addition of nano-sized TiC leads to a greater increase in strength characteristics at room temperature and elevated temperature of 700 °C in comparison with pure Inconel 718 and the addition of micron-sized TiC particles, but also leads to decreasing elongation. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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11 pages, 1938 KiB

Open AccessArticle

Specific Surface Area Evolution and Shrinkage Control of Pre-Sintered Nickel Clusters

by Fengshi Zheng, Linshan Wang, Shaoming Zhang, Lin Zhang, Qiang Hu and Limin Wang

Metals 2022, 12(10), 1693; https://doi.org/10.3390/met12101693 - 10 Oct 2022

Viewed by 1219

Abstract

This study prepared pre-sintered clusters with fine nickel powders and proposed an effective method to predict and control the sintering shrinkage based on cluster size. Experiments were conducted to investigate the influence of the pre-sintering temperature and cluster size on the specific surface [...] Read more.

This study prepared pre-sintered clusters with fine nickel powders and proposed an effective method to predict and control the sintering shrinkage based on cluster size. Experiments were conducted to investigate the influence of the pre-sintering temperature and cluster size on the specific surface area and morphology of pre-sintered clusters as well as to validate the availability of the proposed shrinkage prediction method. The results show that the specific surface area decreases with an increasing pre-sintering temperature and slightly oscillates with an increasing cluster size. The linear shrinkage ratio is inversely proportional to the cluster size and decreases with an increasing pre-sintering temperature, which begins to drop rapidly at 500 °C and decreases from 19.05% to 3.18% at 800 °C. The experimental results are quite approximate to the predicted values, which strongly prove the availability of the proposed shrinkage prediction method. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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12 pages, 5165 KiB

Open AccessArticle

Process Parameters Optimisation for Mitigating Residual Stress in Dual-Laser Beam Powder Bed Fusion Additive Manufacturing

by Wenyou Zhang, William M. Abbott, Arnoldas Sasnauskas and Rocco Lupoi

Metals 2022, 12(3), 420; https://doi.org/10.3390/met12030420 - 27 Feb 2022

Cited by 7 | Viewed by 2264

Abstract

Laser beam powder bed fusion (PBF-LB) additive manufacturing (AM) is an advanced manufacturing technology that manufactures metal components in a layer-by-layer manner. The thermal residual stress (RS) induced by the repeated heating–melting–cooling–solidification processes of AM is considered to limit the wider uptake of [...] Read more.

Laser beam powder bed fusion (PBF-LB) additive manufacturing (AM) is an advanced manufacturing technology that manufactures metal components in a layer-by-layer manner. The thermal residual stress (RS) induced by the repeated heating–melting–cooling–solidification processes of AM is considered to limit the wider uptake of PBF-LB. A dual-laser beam PBF-LB strategy, with an additional auxiliary laser and reduced power, working in the same powder bed simultaneously, was recently proposed to lower RS within the manufactured components. To provide insights into the optimum PBF-LB AM configurations and process parameters for dual-laser PBF-LB, this study proposed three different coordinated heating strategies (i.e., parallel heating, post-heating, and preheating) of the auxiliary heat source. The temperature fields and RS of dual-laser beam PBF-LB, for Ti-6Al-4V with different process parameters, were computationally investigated and optimized by the thermo-mechanically coupled 3D models. Compared with the single beam PBF-LB, parallel heating, post-heating, and post-heating strategies were proved as effective approaches to reduce RS. Among these, the preheating scanning is predicted to be more effective in mitigating RS, i.e., up to a 10.41% RS reduction, compared with the single laser scanning. This work could be beneficial for mitigating RS and improve the mechanical properties of additively manufactured metal components. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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10 pages, 9957 KiB

Open AccessArticle

Microstructure and Mechanical Properties at Elevated Temperature of Powder Metallurgy Al-Zn-Mg-Cu Alloy Subjected to Hot Extrusion

by Weihao Han, Yang Li, Pei Li, Guoping Su, Chenzeng Zhang, Chunfang Sun, Cunguang Chen, Fang Yang and Zhimeng Guo

Metals 2022, 12(2), 259; https://doi.org/10.3390/met12020259 - 29 Jan 2022

Cited by 3 | Viewed by 2201

Abstract

In this work, Al-Zn-Mg-Cu powders containing 0.15 and 0.33 wt % oxygen were utilized to prepare high-strength aluminum alloys through the process of cold isostatic pressing, sintering, hot extrusion, and heat treatment. Microstructural and mechanical properties at elevated temperatures of 250, 350, and [...] Read more.

In this work, Al-Zn-Mg-Cu powders containing 0.15 and 0.33 wt % oxygen were utilized to prepare high-strength aluminum alloys through the process of cold isostatic pressing, sintering, hot extrusion, and heat treatment. Microstructural and mechanical properties at elevated temperatures of 250, 350, and 450 °C were investigated by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and high-temperature tensile tests. Results showed that the tensile strengths of the obtained Al-Zn-Mg-Cu alloys with 0.15 wt % oxygen were 185, 46, and 18 MPa at 250, 350, and 450 °C, respectively. When the oxygen content of Al-Zn-Mg-Cu alloy rose to 0.33 wt %, the tensile strengths at the corresponding temperature reached up to 205, 68, and 25 MPa, respectively. The excellent high-temperature performance could be attributed to double hindrance to dislocation motion and grain boundary migration by a large amount of nano γ-Al₂O₃ created by the in-creased oxygen, thereby resulting in fine grains even at high temperatures. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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13 pages, 45194 KiB

Open AccessArticle

Extrusion-Based 3D Printing of CuSn10 Bronze Parts: Production and Characterization

by Ahmet Çağrı Kılınç, Ali Aydın Goktas, Özgür Yasin Keskin and Serhan Köktaş

Metals 2021, 11(11), 1774; https://doi.org/10.3390/met11111774 - 04 Nov 2021

Cited by 7 | Viewed by 2822

Abstract

The interest in producing cost-effective 3D printed metallic materials is increasing day by day. One of these methods, which has gained much attention recently, is the fused deposition modelling (FDM) method. The parameters used in the FDM method have significant effects on the [...] Read more.

The interest in producing cost-effective 3D printed metallic materials is increasing day by day. One of these methods, which has gained much attention recently, is the fused deposition modelling (FDM) method. The parameters used in the FDM method have significant effects on the printed part properties. In this study, CuSn10 bronze alloy was successfully produced. The printing speed and layer thickness were investigated as the printing process parameters, and their effect on morphological properties was characterized by using SEM. As a result, it was observed that the formation of printing-induced voids was prevented by applying a layer thickness of 0.2 mm. Additionally, by increasing printing speed, a slight decrease in product density was observed. Following determination of 3D printing parameters which give the highest printed part density, the parts were debound in hexane solution via solvent debinding. Finally, the parts were sintered at 850, 875 and 900 °C for 5 h to examine effect of sintering temperature on density, porosity, shape deformation and mechanical properties. Although partial slumping started to form over 875 °C, the highest density (94.19% of theoretical density) and strength (212 ± 17.72 MPa) were obtained by using 900 °C as the sintering temperature. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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11 pages, 8230 KiB

Open AccessArticle

Effect of Filler Metal Type on Microstructure and Mechanical Properties of Fabricated NiAl Bronze Alloy Using Wire Arc Additive Manufacturing System

by Jaewon Kim, Jaedeuk Kim, Jooyoung Cheon and Changwook Ji

Metals 2021, 11(3), 513; https://doi.org/10.3390/met11030513 - 19 Mar 2021

Cited by 6 | Viewed by 2220

Abstract

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. [...] Read more.

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κ_III structure with β′ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κ_III structure in between. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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29 pages, 12319 KiB

Open AccessReview

A Review of Additive Manufacturing Techniques and Post-Processing for High-Temperature Titanium Alloys

by Binquan Jin, Qing Wang, Lizhong Zhao, Anjian Pan, Xuefeng Ding, Wei Gao, Yufeng Song and Xuefeng Zhang

Metals 2023, 13(8), 1327; https://doi.org/10.3390/met13081327 - 25 Jul 2023

Cited by 6 | Viewed by 2496

Abstract

Owing to excellent high-temperature mechanical properties, i.e., high heat resistance, high strength, and high corrosion resistance, Ti alloys can be widely used as structural components, such as blades and wafers, in aero-engines. Due to the complex shapes, however, it is difficult to fabricate [...] Read more.

Owing to excellent high-temperature mechanical properties, i.e., high heat resistance, high strength, and high corrosion resistance, Ti alloys can be widely used as structural components, such as blades and wafers, in aero-engines. Due to the complex shapes, however, it is difficult to fabricate these components via traditional casting or plastic forming. It has been proved that additive manufacturing (AM) is an effective method of manufacturing such complex components. In this study, four main additive manufacturing processes for Ti alloy components were reviewed, including laser powder bed melting (SLM), electron beam powder bed melting (EBM), wire arc additive manufacturing (WAAM), and cold spraying additive manufacturing (CSAM). Meanwhile, the technological process and mechanical properties at high temperature were summarized. It is proposed that the additive manufacturing of titanium alloys follows a progressive path comprising four key developmental stages and research directions: investigating printing mechanisms, optimizing process parameters, in situ addition of trace elements, and layered material design. It is crucial to consider the development stage of each specific additive manufacturing process in order to select appropriate research directions. Moreover, the corresponding post-treatment was also analyzed to tailor the microstructure and high-temperature mechanical properties of AMed Ti alloys. Thereafter, to improve the mechanical properties of the product, it is necessary to match the post-treatment method with an appropriate additive manufacturing process. The additive manufacturing and the following post-treatment are expected to gradually meet the high-temperature mechanical requirements of all kinds of high-temperature structural components of Ti alloys. Full article

(This article belongs to the Special Issue Additive Manufacturing of Non-ferrous Alloys)

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