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Purpose: The selective laser melting (SLM) technique, as a typical additive manufacturing process, is widely used for the fabrication of metallic biomedical components. In terms of biodegradability, zinc and its alloys represent an emerging generation of metallic materials for biomedical implants. The purpose of this paper is to obtain the Zn and Zn10Mg alloys with high mechanical properties using the SLM technology. The relationship between the processing parameters and the porosity of pure Zn and Zn10Mg alloy samples was investigated. Design/methodology/approach: The samples were fabricated using SLM technology working in an inert gas closed chamber. Preliminary experiments were conducted to analyze the laser power and gas flow on evaporation, single track form and porosity. To evaluate the influence of factors on relative density, the response surface methodology was applied. Findings: The satisfactory results of the proposed method were achieved, in which the relative density of the components reached up to 99.63%, and compression strength reached 214 ± 13 MPa under optimal processing conditions. Originality/value: Zinc is categorized by its low melting and boiling point, which leads to the high porosity of the components. It is difficult to prepare the Zn alloy samples with high relative density using SLM technology. This work successfully achieved dense Zn and Zn10Mg samples and investigated their microstructure, mechanical properties and corrosion behavior. [ABSTRACT FROM AUTHOR]

Titanium-tantalum (Ti-Ta) alloy has excellent biomechanical properties with high strength and low Young's modulus, showing great application potential in the biomedical industry. In this study, Ti-Ta alloy samples were prepared by laser powder bed fusion (LPBF) technology with mixed pure 75 wt.% Ti and 25 wt.% Ta powders as the feedstock. The maximum relative density of Ti-Ta samples prepared by LPBF reached 99.9%. It is well-accepted that four nonequilibrium phases, namely, α′, α″ and metastable β phase exist in Ti-Ta alloys. The structure of α′, α″ and β are hexagonal close-packed (HCP), base-centered orthorhombic (BCO) and body-centered cubic (BCC), respectively. X-ray Diffraction (XRD) analysis showed that the α′ phase transformed to the α″ phase with the increase of energy density. The lamellar α′/α″ phases and the α″ twins were generated in the prior β phase. The microstructure and mechanical properties of the Ti-Ta alloy were optimized with different LPBF processing parameters. The samples prepared by LPBF energy density of 381 J/mm3 had a favorable ultimate strength (UTS) of 1076 ± 2 MPa and yield strength of 795 ± 16 MPa. The samples prepared by LPBF energy density of 76 had excellent ductility, with an elongation of 31% at fracture. [ABSTRACT FROM AUTHOR]

The additive manufacturing (AM) 3D printing technique is the most feasible, advanced technology for metal parts that have attracted great attention in the manufacturing industry. AM of titanium alloys by selective laser melting (SLM) is one of the most recent research developments in this field because of its benefits and wide applicability in manufacturing sectors. SLM is an efficient, convenient AM technology that can quickly form complex structures. A well-known titanium alloy named Ti6Al4V, manufactured by SLM, has several practical applications in engineering technology, including cars, space shuttles, and aeronautics. This paper demonstrates the density, sectional morphology, microstructure, and mechanical properties before and after heat treatment of Ti6Al4V alloy sample due to laser power, exposure time, and line spacing. A selective laser melting technology was used to fabricate the Ti6Al4V samples. The results show that the sample defects decreased with the increase in laser power. Moreover, when the laser power was 400 W combined with an exposure time of 30 µs, the sample's tensile strength reached 1203 MPa, almost 300MPa greater than that of ordinary forged Ti6Al4V titanium alloy after annealing. The continuous variation in the line spacing within a certain limit (50-65 µm) could increase the relative density up to 99.59%, which is much better than previously reported results. The tensile fracture of the sample presents a brittle crack. [ABSTRACT FROM AUTHOR]

A dense Cu-10Sn alloy bulk specimen was obtained by optimizing the laser powder bed fusion (L-PBF) processing, and the relative density of the specimen reached 99.7%. The grain morphology was mainly the columnar dendrite and inter-dendritic phases generated along the solidification direction. Tensile testing and detailed microstructural characterization were carried out on specimens in the as-built and heat-treated condition. Under the quasi-static tensile condition, the yield strength (σ0.2), ultimate tensile strength (UTS), and the elongation of the as-built Cu-10Sn specimen were 392 MPa, 749 MPa and 29%, respectively. After the solution treatment at 800 °C for 4 h, and aging treatment at 400 °C for 2 hours, the microstructure of the specimen transformed from the columnar grain to equiaxed grain, the dislocation density decrease, and numerous annealing twins were observed in the heat-treated state. Therefore, the quasi-static tensile yield strength (σ0.2) of the specimen was reduced to 245 MPa. However, the UTS and the elongation were increased to 840 MPa and 56%, respectively, due to the interaction between annealing twins and equiaxed grain. [ABSTRACT FROM AUTHOR]

Purpose: In this research, the highly dense bulk Cu-5Sn alloy specimens were fabricated using selective laser melting (SLM). This study aims to establish the relationship between laser power (LP), scanning speed (SS) and hatch space (HS) with surface roughness (Ra) and density. To obtain Cu-5Sn alloy formed parts with high strength and low surface roughness. The microstructure and mechanical properties of SLMed Cu-5Sn were investigated. Design/methodology/approach: The relative density (RD) was optimized using the response surface method (RSM) and analysis of variance. First, the Ra of SLMed formed specimens was studied to optimize the forming process parameters with a good surface. Then, the dense specimens were studied by ANOVA and the RSM to obtain dense specimens for mechanical property analysis. Findings: Dense specimens were obtained by RSM and ANOVA. The tensile properties were compared with the casted specimens. The yield and ultimate strengths increased from 71 and 131 MPa for the cast specimens to 334 and 489 MPa for the SLMed specimens, respectively. The ductility increased significantly from 11% to 23%, due to the refined microstructure of the SLMed specimens, as well as the formation of many twin crystals. Originality/value: The Ra, RD and mechanical properties of SLM specimens Cu-5Sn were systematically studied, and the influencing factors were analyzed together. This study provides a theoretical and practical example to improve the surface quality and RD. [ABSTRACT FROM AUTHOR]

Pure Copper (Cu) is very difficult to prepare using selective laser melting (SLM) technology. This work successfully prepared the pure Cu with high relative density and high strength by the SLM technology using a surface oxidation treatment. The gas-atomized pure Cu powder was used as the feedstock in this work. Before the SLM process, the pure Cu powder was initially handled using the surface oxidation treatment to coat the powder with an extremely thin layer of Cu2O. The SLMed highly dense specimens contain α-Cu and nano-Cu2O phases. A relationship between the processing parameters (laser power (LP), scanning speed (SS), and hatch space (HS)) and density of Cu alloy in SLM was also investigated. The microstructure of SLMed Cu consists of fine grains with grain sizes ranging from 0.5 to ~30 μm. Tensile testing and detailed microstructural characterization were performed on specimens in the as-SLMed and pure copper state specimens. The mechanical property experiments showed that the specimens prepared by SLM technology containing nano-oxide phases had higher yield strength and tensile strength than that of other SLM-built pure copper. However, the elongation was remarkably decreased compared to other SLM-built pure copper, due to the fine grains and the nano-oxides. [ABSTRACT FROM AUTHOR]

• W-Cu10Sn composite with relative density of 99.36% was fabricated through SLM. • Completely melting W during SLM formed three dimensional connected structure. • Cracks within W were significantly restrained due to the evaporation and melting of Cu10Sn. Three-dimensional connected W-Cu10Sn composites materials with high relative density (99.36%) were fabricated through selective laser melting (SLM). The densification process of the composite balanced the melting of W, evaporation of Cu/Sn and the spreading of melted α-Cu. Under the optimized SLM parameters, high laser power (LP) melted the most of W powder, the adjacent laser scanning track with small hatch space (HS) could fuse W phase together. With small HS and low scanning speed (SS), the spreading of melted α-Cu could fill up the pores caused by the evaporation of Cu/Sn. Finally, a three-dimensional connected structure is formed by W phase, and α-Cu phase occupied the gaps the gaps among W phase. [ABSTRACT FROM AUTHOR]