Selective Laser Melting Alloy Research Articles

Recycling selective laser melting alloy powder on cobalt chromium-to-ceramic bond strength

Statement of problemReusing the powder in selective laser melting machines after multiple cycles is a cost-effective procedure for dental laboratories. However, information on the metal-ceramic bond strength of the framework fabricated by using recycled powder is lacking. PurposeThe purpose of this in vitro study was to investigate how the bonding agent and repeated alloy powder reuse affected the metal-ceramic bond strength of cobalt chromium frameworks fabricated by using selective laser melting. Material and methodsFour square and 40-bar-shaped cobalt chromium frameworks were fabricated by selective laser melting. Half were produced by using virgin alloy powder (Group V; nsquare=2, nbar=20), and half with 30-times reused powder (Group R; nsquare=2, nbar=20). The particle size of each powder was measured by using scanning electron microscopy, and its phase composition was characterized by using radiograph diffraction. Each group was divided into 2 subgroups (Group W [Wash Opaque] and Group N [NP-Bond]) according to the brand of bonding agent used. After ceramic application, the metal-ceramic bond strengths were evaluated by using 3-point bend tests. The bonding agents’ chemical composition was analyzed by using radiograph fluorescence. Bond strength data were analyzed by using a 2-way analysis of variance (α=.05). ResultsMean ±standard deviation bond strengths did not differ significantly (P>.05) between Groups V (31.25 ±4.65) and R (30.88 ±4.78). Group W (35.34 ±1.78) had significantly higher bond strength than Group N (26.80 ±1.74; P<.001). Radiograph diffraction analysis found that the phase composition of all powders was similar. The bonding agent in Group W contained cerium, whereas, that in Group N did not. ConclusionsMetal-ceramic bond strength was unaffected by alloy powder reuse. However, the bonding agent brand may affect the bond strength of cobalt chromium frameworks fabricated by using selective laser melting.

Enhanced mechanical performance of duplex stainless steels via dense core-shell nano-inclusions in-situ formed upon selective laser melting

In this study, with aid of selective laser melting (SLM) and minor Ti addition, we obtain a high density of core-shell structured nano-inclusions with an oxide core and a TiN shell in an S2205 DSS, where the high oxygen concentration originates from the severe oxygen contamination during the making of feedstock powders. These nano-inclusions can not only refine the microstructure by inhibiting the motion of austenite/ferrite interfaces upon the post-SLM annealing, but also contribute to a notable precipitation strengthening increment up to ∼230MPa. The current nano-inclusions strengthened DSS exhibits an attractive mechanical performance with a tensile strength of ∼910MPa and a total elongation of ∼52% yet non-deteriorative corrosion resistance, which has surpassed most of the reported 2205 DSSs. Our results provide a novel route for developing a wide range of nano-architectured SLM alloys with drastically enhanced properties.

Comparison of the Structure, Mechanical Properties and Effect of Heat Treatment on Alloy Inconel 718 Produced by Conventional Technology and by Additive Layer Manufacturing.

The nickel-iron-based alloy Inconel 718 is a progressive material with very good mechanical properties at elevated and lower temperatures. It is used both as wrought and cast alloys as well as material for additive manufacturing technologies. This is the reason why it has received so much attention, as supported by numerous publications. However, these are almost exclusively focused on a specific type of production and processing, and thus only report differences in the mechanical properties between samples prepared by different technologies. Therefore, the major aim of this research was to show how the structure and mechanical properties differ between samples produced by conventional production (wrought alloy) and additively manufactured SLM (Selective Laser Melting). It is shown that by applying appropriate heat treatment, similar strength properties at room and elevated temperatures can be achieved for SLM samples as for wrought samples. In addition, the mechanical properties are also tested up to a temperature of 900 °C, in contrast to the results published so far. Furthermore, it is proven that the microstructures of the wrought (here rolled) and SLM alloys differ significantly both in terms of grain shape and the size and distribution of precipitates.

Significant transitions of microstructure and mechanical properties in laser additive manufacturing AlCoCrFeNi2.1 eutectic high-entropy alloy under heat treatment

In this work, the AlCoCrFeNi2.1 eutectic high-entropy alloys (EHEAs) were fabricated by laser additive manufacturing and subsequently heat-treated at various temperatures between 800 and 1200 °C to achieve excellent strength-plasticity synergy. The high solidification rate of selective laser melting (SLM) leads to instability of the eutectic growth front, resulting in a typical melt pool morphology of equiaxed and columnar crystals for AlCoCrFeNi2.1. The body-centered cubic (BCC) content of ∼82% in the SLM specimens leads to a higher tensile strength of ∼1175 MPa and poorer plasticity of ∼6.42%. After heat treatment, the BCC transforms to face-centered cubic (FCC) and the microstructure changes to a dendrite containing eutectic lamellar structure. As the temperature increases, Ni–Al aggregates, B2 phase particles precipitate and grow in the BCC matrix. Meanwhile, the uniform heating mode eliminates the orientation of the SLM melt pool structure, reduces the internal stress and dislocation density of the SLM alloy. In addition, high-temperature heating promotes the stable growth of lamellar structure. These combined effects allow the strength-plasticity trade-off to be achieved in the heat-treated specimen. The HT-1200 sample has a strength of 1065 MPa and a ductility of 21.97%.

Mechanical Spectroscopy Study of CrNiCoFeMn High-Entropy Alloys.

The equiatomic high-entropy alloy of composition of CrNiCoFeMn with an FCC crystal structure was prepared by either induction melting or additive manufacturing with a selective laser melting (SLM) process, starting from mechanically alloyed powders. The as-produced samples of both kinds were cold worked, and in some cases re-crystallized. Unlike induction melting, there is a second phase, which is made of fine nitride and Cr-rich σ phase precipitates, in the as-produced SLM alloy. Young's modulus and damping measurements, as a function of temperature in the 300-800 K range, were performed on the specimens that were cold-worked and/or re-crystallized. Young's modulus values of (140 ± 10) GPa and (90 ± 10) GPa were measured from the resonance frequency of free-clamped bar-shaped samples at 300 K for the induction-melted and SLM samples, respectively. The room temperature values increased to (160 ± 10) GPa and (170 ± 10) GPa for the re-crystallized samples. The damping measurements showed two peaks, which were attributed to dislocation bending and grain-boundary sliding. The peaks were superposed on an increasing temperature background.

A Comparison of the Microstructure, Mechanical Properties, and Corrosion Resistance of the K213 Superalloy after Conventional Casting and Selective Laser Melting

K213 superalloy was fabricated by conventional casting and selective laser melting (SLM). The microstructures of the two samples were examined, and the mechanical properties and corrosion resistance of these two kinds of K213 alloy were comparatively studied. The results show that segregation of Ti occurs at the grain boundaries of the as-cast alloy, resulting in the formation of MC carbide. Many microcracks were formed in the SLM sample. Premature fracture of the as-cast alloy is caused by the precipitation of the harmful phase (Ti, Mo, Nb)C (MC). The MC carbides and microcracks in the as-cast and SLM alloys, respectively, induce tensile fracture. In comparison, the strength of the SLM sample is greater, while the elongation of the as-cast sample is greater. The oxidation resistance of the SLM sample is better at a high temperature of 800 °C. This is due to the relatively uniform composition and microstructure of the SLM alloy. However, the corrosion rate of the SLM alloy is accelerated during the electrochemical immersion corrosion process due to the existence of microcracks.

Tensile property and microstructure of Al−4.77Mn−1.37Mg−0.67Sc−0.25Zr alloy under different selective laser melting processing parameters

A new Al−4.77Mn−1.37Mg−0.67Sc−0.25Zr alloy (wt.%) was prepared by selective laser melting (SLM) technique under different processing parameters, and the microstructure and mechanical property of the SLM alloys were investigated by tensile tests and microscopy methods. The results show that when the energy density ranges from 104 to 143 J/mm3, the mechanical properties remain relatively stable. The yield strength, ultimate tensile strength and elongation are 335−338 MPa, 397−400 MPa and above 11%, respectively. Meanwhile, few defects and coarse intermetallics form and lots of fine AlFeMnScZr phases precipitate. When the energy density exceeds 152 J/mm3, some cavities and cracks can be observed, and elongation decreases sharply. The quantitative calculation results show that the solid solution strengthening, grain boundary strengthening and precipitation strengthening account for 44%, 41% and 15%, respectively.

Comparatively evaluating the room and high temperature mechanical properties of AlSi10Mg alloy produced by selective laser melting

This work deals with the room and high-temperature mechanical properties of selective laser melted (SLMed) AlSi10Mg alloy through conducting compression testing method in a wide range of temperatures (25–450 °C) under the strain rate of 0.001s−1. The mechanical properties have been compared with those obtained for thixo-cast A356 alloy and AlCuMg2Si in-situ composite at the same thermomechanical condition. The SLMed AlSi10Mg alloy represented a substantially higher fracture toughness especially at low-temperature regime. Where AlCuMg2Si in-situ composite was fractured at 250 °C; and thixocast A356 alloy at 150 °C, the SLMed AlSi10Mg alloy tolerated high amount of strain at room temperature and experienced flow stress softening at 150 °C and 250 °C. The SLMed alloy possessed higher compressive yield strength than other samples at all test temperatures. The peak strains were expectedly decreased with the increase in temperature, however, the SLMed alloy kept its stability almost up to 350 °C. The softening fraction remained relatively constant (<14%) up to 250 °C and then suddenly increased to 22% by further temperature increment to 350 °C which may indicate the change in governing softening mechanisms. The degree of barreling was lower in the case of SLMed AlSi10Mg alloy which meant a higher ability of strain accommodation and capability for strain distribution, which was consistent with high imposed strain tolerated at various temperatures.

The effect of electrospark deposition using zirconium electrodes on structure and properties of nickel-containing alloy obtained selective laser melting

Protective coatings were applied by electrospark deposition (ESD) using zirconium electrodes to improve the performance of the Ni-containing alloy obtained using the selective laser melting (SLM) technology. The kinetics of mass transfer was studied in 5 different frequency-energy processing modes. An analog-to-digital converter was used to determine the average number of pulse discharges, single-pulse energy, and the total energy of pulse discharges for 1 min of processing (ΣЕ) for all the modes used. In low-energy processing modes (ΣЕ = 1459÷2915 J), a weak mass transfer was observed, and the cathode weight gain was recorded only in the first minutes. As the processing time increased, a decrease in the substrate weight was observed. The roughness of coatings (Ra) varied in the range of 3.9–7.2 μm. In high-energy modes (ΣЕ = 5197÷17212 J), due to intense electrode heating, a steady cathode weight gain was observed, but the formed coatings featured by increased roughness: Ra = 7.4÷8.6 μm. The Ra parameter for the original SLM samples was 10.7 μm. The formed coatings featured by a thickness of 15–30 μm, high continuity (up to 100 %), hardness of 9.0–12.5 GPa, elastic modulus of 122–145 GPa, and friction coefficient of 0.36–0.49. The ESD processing promoted an increase in wear resistance of the SLM alloy by 7.5–20 times, and oxidation resistance by 10–20 % (t = 1150 °C, τ = 30 h). It was found that the coating obtained in the low-energy ESD mode with energy ΣЕ = 2915 J featured the best performance (hardness, modulus of elasticity, roughness, wear resistance and oxidation resistance).

Defect, microstructure and mechanical properties of Mg–Gd binary alloy additively manufactured by selective laser melting

The high-performance rare earth magnesium alloys such as Mg–Gd based alloys are becoming the research focus of Mg industry. In this paper, a series of Mg-xGd (x = 3, 6, 10, 15, wt. %) binary alloys were additively manufactured by using the selective laser melting (SLM) technology. The influence of Gd content on the defects, microstructures, and mechanical properties of the SLM alloys were studied. The result shows that the Mg-3Gd, Mg-6Gd, and Mg-10Gd SLM samples are well-built with high density. In contrast, macro-cracks growing perpendicular to build direction occasionally occur on the Mg-15Gd samples. The phase composition of all the SLM samples includes α-Mg matrix and Gd2O3 oxidation inclusion, and the Mg-6Gd, Mg-10Gd, and Mg-15Gd samples also contains eutectic β-Mg5Gd. With the increase of Gd content, the morphology of the eutectic β-Mg5Gd turns from lamellar to network-like, whilst the grain morphology of the α-Mg matrix changes from coarse columnar to fine equiaxed and the texture intensity decreases. The increase of Gd content enhances the effects of fine grain strengthening and secondary phase strengthening, so that the microhardness and tensile strength of the SLM samples improve accordingly. The average microhardness and ultimate tensile strength of the Mg-15Gd SLM sample are as high as 106.9 HV and 386 MPa, respectively. On the other hand, the elongation of the SLM alloys shows a “Λ-shaped” variation trend with the increase of Gd content, reaching the maximum value when the Gd content is 10 wt %, due to the combined influence of the changes in grain size, texture intensity, and the morphology of eutectic β-Mg5Gd. Despite the SLM Mg-15Gd alloy has the highest microhardness and tensile strength, its practicality is restricted by the occasional formation of macro-cracks.

Analysis of microstructure and fatigue of cast versus selective laser-melted dental Co-Cr alloy

Statement of problemThe forces exerted on teeth and prostheses during mastication are repeated and dynamic, resulting in fatigue damage to dental prostheses. Most fractures of dental restorations are fatigue failure. The 4-point bend fatigue behavior of Co-Cr-Mo-W alloys manufactured by investment casting (CAST) and selective laser melting (SLM) has received little attention. PurposeThe purpose of this in vitro study was to evaluate the 4-point bend fatigue property of dental Co-Cr alloys and determine the relationship between microstructure and the 4-point bend fatigue property of Co-Cr alloys created by traditional casting and SLM. These can guide the use of Co-Cr alloy in dentistry. Material and methodsCo-Cr-Mo-W alloys were fabricated with a dimension of 45×2×2 mm by investment casting and SLM. The 3-point bend test measured the ultimate bend strength with 3 specimens in each group. The 4-point bend fatigue test evaluated the fatigue life under various stresses, with 6 specimens in each group. The specimens were mechanically ground, polished, and electrochemically etched. Scanning electron microscopy was used to identify the microstructures of both etched specimens and fracture surfaces. X-ray diffraction investigations were used to determine the phases. Significant differences in the bend strength were analyzed by using the independent samples t test (α=.05), and the fatigue test was analyzed with ANCOVA (α=.05). ResultsThe mean ±standard deviation bend strength of SLM specimens was 1837 ±3 MPa, higher than the 1200 ±6 MPa for CAST specimens (P<.05). The maximum bend stress of the SLM specimens without fatigue failure was 735 MPa, which was statistically higher than the 394 MPa for CAST specimens (P<.05). The microstructure characteristics of the SLM alloy contributed to its excellent fatigue performance. In SLM alloy, the γ phase constituted the majority with some ε and Laves phases, while the cast alloy possessed higher ε and Laves phases. The grains of SLM alloy were equiaxed and fine, and the second phases were fine and dispersive. In contrast, the cast alloy possessed clear dendrites, and the second phases were sizable. ConclusionsThe SLM dental Co-Cr-Mo-W alloy had statistically better 4-point bend fatigue properties than cast alloy, which was associated with an improved microstructure.

Selective laser melting of the Al0.3CoCrFeNiCu high-entropy alloy: Processing parameters, microstructure and mechanical properties

The as-printed Al0.3CoCrFeNiCu high-entropy alloy (HEA) was fabricated from gas-atomized powders by selective laser melting (SLM) with the tailored printing parameters. The processing parameters, microstructural characteristics, mechanical properties and formed defects of the SLM-processed Al0.3CoCrFeNiCu HEA were examined in detail. The SLM-processed HEAs presented a simple disordered face centered cubic solid solution with columnar grains growing along the building direction and exhibiting a 〈001〉 preferred orientation. Dendritic-segregation, a common phenomenon occurring in as-cast counterparts was eliminated, thus providing a significant method to form a single-phase solid solution. The cellular structure in the columnar grains germinated perpendicular to the boundary of molten pools. In addition, dislocations induced by internal stress were observed. Accordingly, the SLM-processed Al0.3CoCrFeNiCu HEA exhibited superior microhardness and compressive strength. Finally, two types of defects were found in this SLM alloy, including irregular holes and hot cracks. The latter occurring on solid–liquid interface of molten pool were retarded by grain boundaries and then turned into muti-branches. Nevertheless, no crack-free sample could be prepared even though the printing parameters were optimized to achieve a high relative density of 99.08%, indicating this HEA was not suitable for SLM technology to prepare.

Characterization of microstructure and hardening of SLM nickel-based alloy irradiated by He ions

For the application of additively manufactured nickel-based alloys in molten salt reactors (MSRs), it is crucial to evaluate their performance in nuclear environments, especially under He-induced damage. Therefore, in this study, the irradiation damage behaviour of selective laser melted (SLM) nickel-based GH3536 alloy was studied by irradiating it with He ions at various doses. Traditionally manufactured (TM) materials were used as reference materials to evaluate the resistance of SLM GH3536 to irradiation. Transmission electron microscopy (TEM) was performed to reveal the depth distribution of irradiation-induced He bubbles, as well as the characteristics of dislocation loops, using both on-zone scanning transmission electron microscopy (STEM) and rel-rod modes. Nanoindentation tests were performed on both alloys to investigate their irradiation hardening. The TEM graphs and quantitative analysis showed that, owing to the cellular sub-grain structures, the He bubbles in the SLM alloy exhibited a lower number density but larger size than those in the TM alloy. Additionally, the SLM alloy showed inferior He tolerance but better resistance to irradiation hardening, as revealed by the nanoindentation test results. Consistency between the experimental hardness increment and calculated yield stress increment showed that the irradiation hardening of the sample was mainly caused by the presence of irradiation-induced defects. A comparison between the on-zone STEM and rel-rod modes suggested that the rel-rod mode is more effective if only the effect of irradiation-induced defects on mechanical properties is studied. Furthermore, this study provides insight into the design of SLM nickel-based alloys for nuclear industry applications.

Wear Resistance and Biocompatibility of Co-Cr Dental Alloys Fabricated with CAST and SLM Techniques.

Cobalt–chromium (Co-Cr) alloys have been widely used as dental-restoration materials for many years. This study sought to investigate whether selective laser melting (SLM) is a more appropriate process than traditional casting (CAST) for fabricating dental Co-Cr alloys. Metallurgical microscopy, X-ray photoelectron spectroscopy (XPS), Vickers hardness and nanoindentation tests, and friction and wear tests were used to evaluate the microstructure, surface compositions, mechanical properties, and wear resistance, respectively. Additionally, the biocompatibilities and cell adhesion of the alloys were evaluated with L-929 fibroblasts via CCK-8 assay, Live/Dead staining, flow cytometric analysis, scanning electron microscopy (SEM) observation and real-time PCR (RT-PCR) assay. The XPS results showed that the two alloys were all mainly comprised of Co, Cr, and O. The hardness in the CAST group equaled 7.15 ± 0.48 GPa, while in the SLM group, it equaled 9.06 ± 0.49 GPa. The friction coefficient of SLM alloys remained at approximately 0.46, but the CAST specimens fluctuated significantly. SLM alloys exhibited shallower wear scars and less wear debris compared with CAST alloys, simultaneously. Additionally, there were higher survival and expression of cell-adhesion-related genes on SLM alloys of L-929 cells, which meant that the deleterious effect on L-929 cells was significantly reduced compared with that for the CAST alloys. Overall, the wear resistances and biocompatibilities of the Co-Cr dental alloys were dramatically affected by the fabrication technique. The SLM technique is advantageous over the CAST technique for fabricating Co-Cr dental alloys.

Microstructural evolution and strengthening mechanism of high-strength AlSi8.1 Mg1.4 alloy produced by selective laser melting

A high-strength AlSi8.1Mg1.4 aluminum alloy was specifically designed for selective laser melting (SLM) by doubling the Mg content of A357 alloy based on the rapid solidification characteristics of the SLM process. The alloy showed good processability with maximum density over casting alloy with the same composition. The microstructure of the as-built alloy was characterized by the formation of cell structure. The α-Al cells manifested GP zones/Mg-Si clusters. The yield strength (YS), ultimate tensile strength (UTS), and elongation to fracture of the as-built alloy were 341 ± 14 MPa, 518 ± 6 MPa, and 7.1 ± 0.4%, respectively. Due to the precipitation of β″ nanoparticles in α-Al cells, the strength of the SLM alloy was effectively improved after direct aging at 150 ℃ and 200 ℃, with a maximum YS of 446 ± 5 MPa and maximum UTS of 546 ± 1 MPa, which were much higher than those of Al-Si-based alloy produced by SLM. When the aging temperature exceeded 200 ℃, the strength of the alloys decreased rapidly, but the elongation increased significantly. Multiple strengthening mechanisms, including grain refinement, GP zones/Mg-Si clusters, and β″ nanoparticle precipitation contributed to the high strength of SLM AlSi8.1Mg1.4 alloy.

Anisotropic damage evolution and modeling for a nickel-based superalloy built by additive manufacturing

The objective of the present work is to characterize the effects of microstructural features, including porosity, precipitates, and to quantify their contributions to the damage evolution in the Inconel 718 alloy built by selective laser melting (SLM). 3D morphology of porous defects in the SLM alloy obtained from X-ray micro-computed tomography before and after hot isostatic pressing (HIP) were analyzed and classified based on the pore size, shape, and distribution. The unmelt region pores with the large size and irregular shape are found serving as crack sources and responsible for the anisotropic damage evolution. The inter-dendritic precipitated phases and twin boundaries were observed and preferred to be crack initiation sites and propagation paths, which further promote microstructural damage evolution. The macroscopic anisotropic damage of Inconel 718 alloy was evaluated through the variations of the material stiffness measurement from tensile tests with multiple unloading steps. A microstructure-dependent damage model was introduced to quantitatively describe the contributions of the microstructures o the evolution of macroscopic material degradation. The total damage was decomposed into three components based on the microstructural mechanisms and gives meaningful evolution laws of the microstructural characteristics. The material stiffness degradation processes of SLM can be predicted by the present model with good agreement.

Investigation on electron beam welding of dissimilar wrought/selective laser melting AISI 304 stainless steel plates

The selective laser melting (SLM) process gives a possibility to create complex shape parts. Joining SLM alloy parts to similar or dissimilar alloy parts can overcome some product design limitations such as limited dimensions and residual stress concentration. In this study, successful electron beam joining work on to SLM AISI 304 stainless steel plates was performed. The influence of beam current on the weld bead profile was investigated. Typical welded joints were analyzed by microstructure, microhardness, and tensile tests. The optimal welding parameters were obtained accordingly. A thorough analysis of the element and microstructure distribution in SLM and its influence on the properties of the welded joints were also investigated.

Simultaneous strength and ductility enhancements of high thermal conductive Ag7.5Cu alloy by selective laser melting

High electrical and thermal conductive metals (HETCM) play a key role in smart electronics, green energy, modern communications and healthcare, however, typical HETCM (e.g., Ag, Au, Cu) usually have relatively low mechanical strength, hindering further applications. Selective laser melting (SLM) is a potentially transformative manufacturing technology that is expected to address the issue. Ag is the metal with the highest thermal conductivity, which induces microscale grain refinement, but also leads to high internal stresses by SLM. Here, we select Ag7.5Cu alloy as an example to demonstrate that multi-scale (micro/meso/macro) synergies can take advantage of high thermal conductivity and internal stresses to effectively strengthen Ag alloy. The mimicry of metal-hardened structures (e.g., large-angle boundary) is extended to the mesoscale by controlling the laser energy density and laser scanning strategy to manipulate the macroscale internal stress intensity and mesoscale internal stress direction, respectively, to form mesoscale large-angle "grains", resulting in multiple mutual perpendicular shear bands during fracture. The presented approach achieved a significant enhancement of yield strength (+ 145%) and ductility (+ 28%) without post-treatment. The results not only break the strength-ductility trade-off of conventional SLM alloys, but also demonstrate a multi-scale synergistic enhancement strategy that exploits high thermal conductivity and internal stresses.

Investigation of the influence of the parameters of selective laser fusion of metal powders and cold isostatic pressing on the structure and mechanical properties of a nickel-based heat-resistant alloy

The influence of the parameters of selective laser melting (SLM) of metal powders and cold isostatic pressing (CIP) of samples from a high-chromium heat-resistant alloy on the microstructure of the processed alloy, the size and number of formed pores is investigated. The use of HIP for SLM alloys makes it possible to reduce the number and size of pores. The strengthening effect of deformation (increase in hardness) at normal temperature is established. Keywords: selective laser melting, additive manufacturing, track, pores, cold isostatic pressing, mechanical properties, microstructure. remshev@mail.ru, Galina@mail.ru, grisha.afimin@mail.ru, gulyarenko@mail.ru

Experimental investigation of adhesion strength of dental ceramic to Ti6Al4V alloy fabricated by milling and selective laser melting

The aim of the present paper is to investigate the bond strength of dental ceramic to Ti6Al4V alloy fabricated by milling and selective laser melting (SLM). The adhesion strength is studied by 3-point flexural test of samples with porcelain coating. Two groups of specimens are manufactured by milling and SLM. Four different surface treatments are used before porcelain application - no surface treatment (control), sandblasting and application of bonding agent on untreated and sandblasted surfaces. The coating of leucite-reinforced glass-ceramic is manufactured on the one side of the samples. It is found that the adhesion strength of the porcelain coating to the titanium alloy produced by both methods has close values: 17.63 – 30.89 MPa for the milled and 22.12 – 31.04 MPa for the SLM alloy. The surface treatments of the metal substrate have different effect on the adhesion strength. Sandblasting and combined treatment increase the adhesion strength of the porcelain to the milled samples, but decrease that in the SLM ones. The application of the given bonding agent decreases the adhesion strength of the ceramic to the Ti6Al4V alloy produced by both technologies. In the milled alloy, the highest adhesion strength is in the sandblasted samples, followed by these with combined treatment, while for the SLM samples, the adhesion strength in the control group is the highest, followed by the sandblasted samples. Milled samples treated with the given bonding agent, and SLM specimens with combined surface treatment do not meet the required 25 MPa of the standard.