Ultrasonic Evaluation of Laser Scanning Speed Effect on the Spectral Properties of Three-Dimensional-Printed Metal Phononic Crystal Artifacts.

Additive manufacturing/three-dimensional printing (AM/3DP) processes promise a flexible production modality to fabricate a complex build directly from its digital design file with minimal postprocessing. However, some critical shortcomings of AM/3DP processes related to the build quality and process repeatability are frequently experienced and reported in the literature. In this study, an in situ real-time nondestructive monitoring framework based on the dispersive properties of phononic crystal artifacts (PCAs) to address such quality challenges is described. Similar to a witness coupon, a PCA is printed alongside a build while it is interrogated and monitored with ultrasound. A PCA is substantially smaller than the actual build. Due to its periodic internal structures, a PCA creates pass and stop bands in its spectral response, which are sensitive to the variations in its process and material parameters. These periodic structures, representing the geometric complexities of an actual build, are designed for a specific monitoring objective(s) in AM/3DP. As a model application, in this demonstration study, the effect of the laser scanning speed of a slective laser melting (SLM) printer on the spectral properties of metal PCAs (mPCAs) is ultrasonically evaluated offline. The dependency of the pressure and shear wave speeds, the apparent Young's and shear moduli, and Poisson's ratio on the scanning speed are quantified, and it is found that they are highly sensitive to the laser scanning speed of an SLM printer. The sensitivity of the peaks of the pressure and shear spectral waveforms acquired for the identical mPCA designs printed on the same build plate with the same process parameters is also quantified. For powder-based AM/3DP technologies, where scanning speed is among the crucial process parameters such as laser power and bed temperature, the reported correlations between scanning speeds and the mechanical and spectral features of the mPCAs are expected to be instrumental in developing in situ real-time monitoring systems.

Effect of polishing process on torque loss ratio and microgap of selective laser melting abutment: an in vitro study.

BACKGROUND: The purpose of this in vitro study was to investigate the effect of polishing post-treatment process on the torque loss ratio and microgap of Selective Laser Melting (SLM) abutments before and after mechanical cycling test through improving the surface roughness of the implant-abutment interface. MATERIALS AND METHODS: Forty SLM abutments were fabricated, with 20 underwent minor back-cutting, designated as polishing, in the implant-abutment interface. The abutments were divided into three groups: SLM abutments (group A), original abutments (group B), and polished SLM abutments (group C), each containing 20 abutments. Surface roughness was evaluated using a laser microscope. Implant-abutment specimens were subjected to mechanical cycling test, and disassembly torque values were measured before and after. Scanning electron microscope (SEM) was used to measure microgap after longitudinal sectioning of specimens. Correlation between surface roughness, torque loss ratio, and microgap were evaluated. LSD's test and Tamhane's T2 comparison were used to analyze the data (α = 0.05). RESULTS: The Sz value of polished SLM abutments (6.86 ± 0.64 µm) demonstrated a significant reduction compared to SLM abutments (26.52 ± 7.12 µm). The torque loss ratio of polished SLM abutments (24.16%) was significantly lower than SLM abutments (58.26%), while no statistically significant difference that original abutments (18.23%). The implant-abutment microgap of polished SLM abutments (2.38 ± 1.39 µm) was significantly lower than SLM abutments (8.69 ± 5.30 µm), and this difference was not statistically significant with original abutments (1.87 ± 0.81 µm). A significant positive correlation was identified between Sz values and the ratio of torque loss after cycling test (r = 0.903, P < 0.01), as well as Sz values and the microgap for all specimens in SLM abutments and polished SLM abutments (r = 0.800, P < 0.01). CONCLUSION: The findings of this study indicated that the polishing step of minor back-cutting can lead to a notable improvement in the roughness of SLM abutments interface, which subsequently optimized the implant-abutment fit. It can be seen that the application of minor back-cutting method has advanced the clinical use of SLM abutments.

Clinical internal and marginal fit of metal-ceramic fixed dental prostheses fabricated with selective laser melting and 3D-printed pattern casting using cobalt-chromium metal alloy.

PURPOSE: To evaluate the fit of metal-ceramic three-unit fixed dental prostheses (FDPs) fabricated using selective laser melting (SLM) and 3D-printed casting pattern (CP) and to compare the effect of tooth type and ceramic veneering on marginal and internal gaps. MATERIALS AND METHODS: Patients requiring posterior three-unit FDPs were selected. For each subject, two FDPs were fabricated using SLM and CP. Silicon replica was used to measure the internal and marginal fit of frameworks before and after ceramic veneering. For each replica, 36 measurements were performed using a stereomicroscope: 4 marginal and 32 internal (4 deep chamfers, 12 axial, 4 axio-occlusal, and 12 occlusal). Statistical analysis was performed using two-way ANOVA and paired t-test. RESULTS: A total of 44 metal-ceramic FDPs were fabricated in 22 patients. The results showed that the fabrication method had no significant effect on the marginal, deep chamfer, or occlusal gaps. However, the method significantly affected the axial, axio-occlusal, and total internal fit, and the SLM had larger gaps than the CP. For the effect of ceramic veneering, measurements were significantly higher in the CP group at all gaps, except for the premolar axial and molar occlusal gaps. The SLM fit was less affected by ceramic veneering. Only premolar gaps significantly increased at the marginal, deep chamfer, and axial and axio-occlusal positions. CONCLUSION: Metal-ceramic FDPs fabricated using SLM and CP techniques provided a similar marginal fit. Premolars had smaller discrepancies compared to molars. The ceramic veneering process increased the gap of the prostheses, with SLM being less affected by ceramic veneering.

Influence of porous titanium-based jaw implant structure on osseointegration mechanisms.

The reconstruction of maxillofacial defects caused by anomalies, fractures, or cancer is challenging for dentofacial surgeons. To produce efficient, patient-specific implants with long-term performance and biological suitability, numerous methods of manufacturing are utilized. Because additive manufacturing makes it possible to fabricate complex pore structure samples, it is now recognized as an acceptable option to design customized implants. It is well recognized that a porous structure with proper design promotes accelerated cell proliferation, which enhances bone remodeling. Porosity can also be employed to modify the mechanical characteristics of fabricated implants. Thus, design and choice of rational lattice structure is an important task. The influence of the structure of jaw implants made of highly porous titanium-based materials on their mechanical properties and bone tissue growth was studied. Based on a 3D computer model of Wigner-Seitz lattice structure, the model samples were fabricated from Ti6Al4V powder by selective laser melting to characterize the mechanical properties of the samples depending on their macroporosity. Then two types of jaw bone implants were manufactured to conduct studies of bone tissue ingrowth when implanted in laboratory animals. The research was carried out in several stages: design and production of the implants for replacing incomplete defects of the lower jaw; implantation of SLM-printed implants in laboratory animals into an artificially produced defect of the lower jaw; analysis of the degree of fixation of the "implant - bone" connection (for implantation periods from 2 weeks to 9 months). During the research, Ti-alloy structures with cell diameters of 2-3 mm and macroporosity of 90-97% mimicking the spongy structure of trabecular bone tissue, were characterized by a compressive strength of 12.47-37.5 MPa and an elastic modulus of 0.19-1.23 GPa, corresponding to the mechanical properties of bone tissue. Active processes of tissue growth into implant cells were detected 2 weeks after implantation, the significant differences in the volume and types of filling tissue depending on the size of the cell were described. Recommendations for choosing the cell size depending on the type of bone tissue damage were given. When using SLM-printed implants with lattice structure (cell sizes from 1 to 3 mm), an active osteosynthesis processes occurred, which culminated in the formation of bone tissue inside the implant cells 9 months after implantation, with 68% of the samples characterized by the maximum degree of implant fixation. Implants with 3 mm cells with macropores diameters of 850 µm were recommended for replacing cavities after removal of perihilar cysts. To replace complete and partial defects, it was recommended to use implants with a cell size of 2 and 3 mm.

A Review on the Application of Deep Eutectic Solvents in Polymer-Based Membrane Preparation for Environmental Separation Technologies.

The use of deep eutectic solvents (DESs) for the preparation of polymer membranes for environmental separation technologies is comprehensively reviewed. DESs have been divided into five categories based on the hydrogen bond donor (HBD) and acceptor (HBA) that are involved in the production of the DESs, and a wide range of DESs' physicochemical characteristics, such as density, surface tension, viscosity, and melting temperature, are initially gathered. Furthermore, the most popular techniques for creating membranes have been demonstrated and discussed, with a focus on the non-solvent induced phase separation (NIPS) method. Additionally, a number of studies have been reported in which DESs were employed as pore formers, solvents, additives, or co-solvents, among other applications. The addition of DESs to the manufacturing process increased the presence of finger-like structures and macrovoids in the cross-section and, on numerous occasions, had a substantial impact on the overall porosity and pore size. Performance data were also gathered for membranes made for various separation technologies, such as ultrafiltration (UF) and nanofiltration (NF). Lastly, DESs provide various options for the functionalization of membranes, such as the creation of various liquid membrane types, with special focus on supported liquid membranes (SLMs) for decarbonization technologies, discussed in terms of permeability and selectivity of several gases, including CO2, N2, and CH4.

Influence of Defects and Microstructure on the Thermal Expansion Behavior and the Mechanical Properties of Additively Manufactured Fe-36Ni.

Laser-based powder bed fusion of metals (PBF-LB/M) is a widely used additive manufacturing process characterized by a high degree of design freedom. As a result, near fully dense complex components can be produced in near-net shape by PBF-LB/M. Recently, the PBF-LB/M process was found to be a promising candidate to overcome challenges related to conventional machining of the Fe64Ni36 Invar alloy being well known for a low coefficient of thermal expansion (CTE). In this context, a correlation between process-induced porosity and the CTE was presumed in several studies. Therefore, the present study investigates whether the unique thermal properties of the PBF-LB/M-processed Fe64Ni36 Invar alloy can be tailored by the selective integration of defects. For this purpose, a full-factorial experimental design, representing by far the largest processing window in the literature, was considered, correlating the thermal expansion properties with porosity and hardness. Furthermore, the microstructure and mechanical properties were investigated by scanning electron microscopy and quasi-static tensile tests. Results by means of statistical analysis reveal that a systematic correlation between porosity and CTE properties could not be determined. However, by using specific process parameter combinations, the microstructure changed from a fine-grained fan-like structure to a coarse columnar structure.

In-situ tensile testing of fracture and strain in a selective laser melted AlSi10Mg alloy.

The melt pools, the most basic units of the components fabricated by the selective laser melting (SLM) technology, play an important role in the mechanical properties of the structures. A self-developed in-situ tensile observation platform was used to carry out the in-situ tensile test of SLMed AlSi10Mg alloy specimens under the observation of optical microscope. With a series of obtained experimental data on mechanical properties and metallurgical images, combined with the digital image correlation(DIC) technology, the melt pool of the specimen and the strain of defects were analyzed, and the deformation and fracture mechanism of the SLMed AlSi10Mg alloy specimens was obtained. The results show that the proposed method successfully obtains the deformation field evolution data of the melt pool and defects, which provides experimental and theoretical support for the further study of crack extension characteristics and fatigue life prediction of SLMed metallic material components.

Influence of Laser Process Parameters on the Forming Quality and Discharge Performance of 3D-Printed Porous Anodes for Al-Air Batteries.

Aluminum-air (Al-air) batteries are considered one of the most promising next-generation energy storage devices. In this paper, we carry out an orthogonal experimental study on the SLM printing process parameters in 3D-printed Al-air battery anodes. The surface roughness, densification, and discharge performance of the electrodes under different process parameters are observed to reveal the effects of different process parameters on the forming quality and discharge performance of aluminum-air battery anodes. The results show that the laser power is the most important factor affecting the surface roughness of the porous aluminum anode, and the scanning spacing is the most important factor affecting the densification. The best printing parameters for the porous aluminum anode can be obtained when the laser power is 325 W, the scanning speed is 1000 mm/s, the scanning spacing is 0.12 mm, and the thickness of the powder spread is 0.03 mm. At this time, the surface roughness of the porous aluminum anode obtained by this process parameter is 15.01 µm, the densification is 94.97%, and the discharge is stable with a high value. In addition, we also carry out data validation to ensure that the data we obtain are optimal and valid.

The Effect of Ageing on Phase Transformations and Mechanical Behaviour in Ni-Rich NiTi Alloys.

In this article, the results of research on a NiTi alloy with a high nickel content (51.7 at.%), produced using the additive technology SLM method and subjected to isothermal ageing after solution annealing, are presented. The study involved the determination of the sequence of phase transformations occurring using differential scanning calorimetry (DSC) and the determination of the temperature range of these transformations. In parallel, the phase composition was determined using the XRD method; the hardness and the Young's modulus were also determined. The analysis of the DSC results obtained indicates the following characteristic features of the NiTi alloy, which change with ageing time: (1) During cooling (from +150 °C to -50 °C), the type of transformation changes from a one-step transformation after solution annealing to a two-step transformation after the ageing process over 1, 20, and 100 h at 500 °C; (2) during heating (from -50 °C to +150 °C) for all the samples, regardless of the ageing time, only a one-step transformation from martensite M(B19') to austenite A(B2) is observed; (3) the temperature at which the transformation starts increases with the ageing time; (4) the width of the total temperature range of the transformation M(B19') → A(B2) during heating changes from large (ΔT = 49.7 °C), after solution annealing, to narrow (ΔT = 19.3 °C and ΔT = 17.9 °C after 20 h and 100 h of ageing); and, most importantly, (5) a comparison with the literature data shows that, irrespective of the composition of the NiTi alloy and the manufacturing technology of the alloy samples (regardless of whether this was traditional or additive technology), a sufficiently long ageing process period leads to the occurrence of the martensite → austenite transformation in the same temperature range.

Mechanical Behavior of Selective Laser Melting (SLM) Parts with Varying Thicknesses in a Saline Environment under Different Exposure Times.

A promising method for additive manufacturing that makes it possible to produce intricate and personalized parts is selective laser melting (SLM). However, the mechanical properties of as-corroded SLM parts are still areas of concern. This research investigates the mechanical behavior of SLM parts that are exposed to a saline environment containing a 3.5% NaCl solution for varying lengths of time. The exposure times chosen for this study were 10 days, 20 days, and 30 days. The results reveal that the tensile strength of the parts is significantly affected by the duration of exposure. Additionally, the study also examined the influence of porosity on the corrosion behavior of the parts. The analysis included studying the mass loss of the parts over time, and a regression analysis was conducted to analyze the relationship between exposure time and mass loss. In addition, the utilization of scanning electron microscopy (SEM) and X-ray photo spectroscopy (XPS) techniques yielded valuable insights into the fundamental mechanisms accountable for the observed corrosion and mechanical behavior. It was found that the presence of corrosion products (i.e., oxide layer) and pitting contributed to the degradation of the SLM parts in the saline environment. This research emphasizes the importance of considering part thickness in the design of SLM components for corrosive environments and provides insights for enhancing their performance and durability.

An Investigation of the Anisotropic Mechanical Properties of Additive-Manufactured 316L SS with SLM.

Selective laser melting (SLM) forms specimens that often exhibit anisotropic mechanical properties. Most existing research only explains that the mechanical properties of specimens perpendicular to the build direction are superior to those parallel to the build direction. In this paper, the mechanical properties of SLM 316L SS specimens with different surfaces and different directions are compared. Finally, it was found that the mechanical properties of specimens on Face 3 are stronger than those on Face 1 and Face 2, while the mechanical properties of specimens on Face 1 and Face 2 are similar. For specimens in different directions on the same surface, the mechanical properties of Face 1 and Face 2 exhibit clear anisotropy, while the mechanical properties of Face 3 tend to be isotropic. In this paper, the EBSD technique was used to analyze the specimens. It was found that the anisotropy of the mechanical properties of Face 1 and Face 2 are attributed to the presence of texture and columnar crystals in the sample. This paper can provide accurate and reliable material performance data for the practical application of SLM 316L SS, thereby guiding the optimization of engineering design and manufacturing processes.

The Effect of Laser Remelting during SLM on Microstructure and Mechanical Properties of CoCrFeNiNb0.25.

A sub-eutectic high-entropy alloy composed of CoCrFeNiNb0.25 was prepared using a combination of mechanical powder mixing and selective laser melting (SLM). The mechanical properties of the alloy were enhanced by employing an interlayer laser remelting process. This study demonstrates the feasibility of using mechanical mixing and SLM to form an CoCrFeNiNb0.25 alloy. The interlayer laser remelting process can effectively promote the melting of Nb particles introduced by mechanical mixing, release the stresses near the unfused Nb particles, and reduce their degradation of the specimen properties. The results indicate that the CoCrFeNiNb0.25 alloy, prepared using the interlayer laser remelting process, had an average microhardness of 376 HV, a tensile strength of 974 MPa, and an elongation at break of 10.51%. This process offers a viable approach for rapidly adjusting the composition of high-entropy alloys for SLM forming.

A Comparison of the Structure and Selected Mechanical Properties of Cr/Co Alloys Obtained by Casting and Selective Laser Melting.

Selective laser melting (SLM) technologies are becoming increasingly popular. The aim of the work is to compare the metallographic structure, hardness, and selected strength properties of alloys obtained by casting and by SLM, with a particular emphasis on fatigue strength. Twenty Cr/Co alloy bars were made by casting or SLM, and samples of appropriate dimensions were prepared for individual tests. The microstructures of the samples were tested by metallography, and then tested for hardness, impact strength, tensile strength, bending strength, and fatigue strength; they were also subjected to fracture after bending, tensile, fatigue, and impact tests, with the resulting fractures examined by scanning electron microscopy (SEM). Primary dendrites and small amounts of gas bubbles were present in the cast samples ground lengthwise. The SEM samples were more finer grained and uniform. Compared to the casting samples, the SLM samples demonstrated higher hardness, lower mean impact strength and higher tensile strength. The casting samples also displayed lower mean elongation values. The casting samples demonstrated slightly higher fatigue strength. The fractures of the casting samples showed an interdendritic character with clearly visible dendrites at the fracture, while those of the SLM samples were also intergranular, but finer grained. SLM generally results in better strength properties, while casting obtains slightly greater fatigue strength.

The effect of repeated baking of porcelain on its bonding strength to a Co-Cr alloy 3D-printed by selective laser melting.

Objectives: This study aimed to evaluate the effect of multiple baking cycles of porcelain on its shear bond strength to a cobalt-chromium (Co-Cr) alloy that is three-dimensionally printed using Selective Laser Melting (SLM) technique. Materials and methods: The research sample comprised forty-eight discs measuring 5 mm × 3 mm, divided into four groups according to: the manufacturing method (SLM, casting) and the number of porcelain baking cycles (1, 3) as follows: Group A: Co-Cr alloy by SLM with one baking cycle; Group B: Co-Cr alloy by SLM with three baking cycles; Group C: Ni-Cr alloy by casting with one baking cycle; Group D: Ni-Cr alloy by casting with three baking cycles. Then, porcelain was melted on disks, shear testing was performed and the values of the Shear Bond Strength (SBS) in MegaPascals (MPa) were calculated. Results: The mean SBS values for each group were (A: 25.69 - B: 19.51 - C: 35.72 - D: 28.67 MPa). Statistical analysis showed that the manufacturing method and the number of porcelain baking cycles had a significant influence on shear bond durability (P > 0.05): the strength of this bond decreased when baking cycles increased. The Co-Cr samples manufactured by SLM also showed a decrease in binding strength compared to the Ni-Cr samples made by casting. Conclusion: Repeated baking of porcelain reduces the strength of the porcelain bond with the Co-Cr alloy made by Selective Laser Melting (SLM) technique.

Short- to Mid-Term Clinical and Radiological Results of Selective Laser Melting Highly Porous Titanium Cup in Primary Total Hip Arthroplasty.

(1) Background: The aim of this study was to evaluate short- to mid-term clinical and radiological results in patients undergoing primary total hip arthroplasty (THA) with the use of a Selective Laser Melting 3D-printed highly porous titanium acetabular cup (Jump System Traser®, Permedica Orthopaedics). (2) Methods: We conducted a retrospective study and collected prospective data on 125 consecutive patients who underwent primary THA with the use of highly porous titanium cup. Each patient was evaluated preoperatively and postoperatively with a clinical and radiological assessment. (3) Results: The final cohort consisted of 104 patients evaluated after a correct value of 52 (38-74) months. The median Harris Hip Score (HHS) significantly improved from 63.7 (16-95.8) preoperatively to 94.8 (38.2-95.8) postoperatively (p < 0.001), with higher improvement associated with higher age at surgery (ß = 0.22, p = 0.025). On postoperative radiographs, the average acetabular cup inclination and anteversion were 46° (30°-57°) and 15° (1°-32°), respectively. All cups radiographically showed signs of osseointegration with no radiolucency observed, or component loosening. (4) Conclusions: The use of this highly porous acetabular cup in primary THA achieved excellent clinical, functional, and radiological results at mid-term follow-up. A better clinical recovery can be expected in older patients. The radiological evaluation showed excellent osseointegration of the cup with complete absence of periprosthetic radiolucent lines.

Cytoophidia Influence Cell Cycle and Size in Schizosaccharomyces pombe.

Cytidine triphosphate synthase (CTPS) forms cytoophidia in all three domains of life. Here we focus on the function of cytoophidia in cell proliferation using Schizosaccharomyces pombe as a model system. We find that converting His359 of CTPS into Ala359 leads to cytoophidium disassembly. By reducing the level of CTPS protein or specific mutation, the loss of cytoophidia prolongs the G2 phase and expands cell size. In addition, the loss-filament mutant of CTPS leads to a decrease in the expression of genes related to G2/M transition and cell growth, including histone chaperone slm9. The overexpression of slm9 alleviates the G2 phase elongation and cell size enlargement induced by CTPS loss-filament mutants. Overall, our results connect cytoophidia with cell cycle and cell size control in Schizosaccharomyces pombe.

Improving the Surface Quality and Tribological Characteristics of 3D-Printed Titanium Parts through Reactive Electro-Spark Deposition.

This work presents the results of research conducted with an aim to improve the surface quality, hardness and wear resistance of titanium alloy Ti6Al4V, obtained via the laser powder bed fusion of metals (PBF-LB/M) process of additive manufacturing (AM) known as the 3D printing of metals. The 3D surfaces were coated via reactive electrospark deposition (RESD) with low-pulse energy and electrode materials of low-melting metals and multi-component hard alloys. The relationship between the electrical parameters of the RESD process and the quality, composition, structure, microhardness and wear resistance of the treated surfaces were investigated and analysed. It was found that the roughness and thickness of the resulting surface layers could be changed by changing the RESD modes within the limits of 2.5-5 µm and 8-20 µm, respectively. RESD processing allowed us to achieve two to five times lower roughness than that of titanium AM surfaces. The microhardness and wear resistance of the RESD surfaces are two to four times higher than those of the titanium substrate. Possibilities for the purposeful synthesis of new wear-resistant phases and compounds and for obtaining surface layers with predetermined thickness and roughness were established. It was shown that the subsequent reaction's electrospark processing helped to simultaneously reduce the roughness and increase the hardness and wear resistance of the modified surfaces, and can be successfully used instead of the material-energy-labour and machine-intensive finishing treatments of the titanium surfaces obtained after 3D printing.

Influence of Porosity on Fatigue Behaviour of 18Ni300 Steel SLM CT Specimens at Various Angles.

In order to improve understanding of the fatigue behaviour in additive manufactured samples, this research delves into the challenging interplay between building parameters, particularly fabrication angles, and the presence of pores. The primary objective is to explore the characterisation of these pores and unravel their relationship with the fatigue properties of the material under investigation. Through a systematic analysis of porosity distribution in various fabrication orientations, supplemented by a detailed examination of the elemental dispersion around specific porous structures using energy-dispersive X-ray spectroscopy, a consistent behavioural pattern emerges across the samples. In assessing fatigue behaviour, an examination of the variables reveals that only area and aspect ratio significantly influence the behaviour of the samples. Such studies can contribute substantially to academic research in the field of material science and engineering.

Effect of Hatch Spacing on the Quality of Inconel 718 Alloy Part.

Selective laser melting (SLM) has attracted increasing attention all over the world. As an important parameter, hatch spacing, which is the distance between scan lines, however, still needs a more systematic study. In this paper, the relationship between hatch spacing and mechanical properties, including microhardness, wear resistance, and porous density, was studied. The testing results revealed that when hatch spacing decreased, the overlapping rate increased which resulted in an increase in the convection in the molten pool. It led to the formation of pores in the molten pool. However, when hatch spacing was too large, the overlapping zone decreased, while the strength between each welding line was not strong enough. It caused a decrease in the quality of printed parts. Combined with the testing results gained in this work, it can be seen that a 0.06 mm hatch spacing was considered as a relatively optimal condition for part formation under 0.05 µm. Comparison of the morphology of the samples printed under different hatch spacing also confirmed the phenomenon observed here.

Influence of Laser Energy Density on Tribological Properties of AlSi10Mg Manufactured by Selective Laser Melting.

In recent years, much work related to the performance of AlSi10Mg manufactured by selective laser melting (SLM) has been extensively researched. However, the study of tribological performance caused by different laser energy densities is still insufficient. This work concentrates on the relationship between the wear resistance and laser energy density of AlSi10Mg processed using SLM. Moreover, XRD characterization, density, surface roughness and microhardness were also examined since they are closely related to wear resistance. The results revealed that the XRD pattern of AlSi10Mg was mainly composed of the α-Al and Si phases under the conditions of different laser energy densities. In addition, the peak of Mg2Si was also detected. Also, the grain size increased with the increasing of laser energy density. The increase in laser energy density led to an increase in the convection and porous phenomenon in the molten pool. However, when the value was lower, the overlapping area reduced, and the strength between adjacent melting paths was insufficient, resulting in the declination of the sample property. According to the experimental results, a laser energy density of 63.33 J/mm3 was considered to be a relative optimal condition. The relative density, Ra, microhardness and wear volume were 99.2%, 8.86 µm, 128.3 HV0.2 and 2.96 × 10-2 mm3, respectively. The worn surface morphology also confirmed the influence of laser energy density on wear resistance. A regression model was established and analyzed, which showed the reliability of the results. Furthermore, the tribological mechanism was also revealed.