One of the issues that modern implants face is their high stiffness, coupled with a positive Poisson’s ratio along the implant. This creates certain problems with bone inflammation and implant detachment. A possible solution to these problems is TiNi alloy lattice structure implants with low stiffness and negative Poisson’s ratio. This paper presents the results of simulation, fabrication by the SLM technique, and study of lattice structures with negative Poisson’s ratio, which can help to solve said problems. The studies involve the determination of mechanical characteristics, Poisson’s ratio, transformation temperatures, and the potential for a superelasticity effect of the lattice structure. The characteristics obtained at initial simulation were partially confirmed in the course of the works. Moreover, the possibility of fabricating TiNi alloy lattice structures with negative Poisson’s ratio (about −0.00323) and low Young’s modulus values (0.818 GPa) was confirmed by the SLM technique.

Some multi-materials produced via SLM and containing 316L steel may exhibit defects and cracks in the interfacial zone. There is a lack of research on 316L/NiTi multi-materials with an interlayer produced via SLM. This study aims to investigate the influence of a high-entropy alloy (HEA)—CoCrFeNiMn interlayer on the defects’ formation, microstructure, phase, and chemical compositions, as well as the hardness of the interfacial zone. It was concluded that using of high-entropy alloy as an interlayer in the production of 316L/HEA/NiTi multi-material via SLM is questionable, since numerous cracks and limited pores occurred in the HEA/NiTi interfacial zone. The interfacial zone has an average size of 100–200 μm. Microstructure studies indicate that island macrosegregation is formed in the interfacial zone. The analysis of phase, chemical composition, and hardness demonstrates that a small amount of FeTi may form in the island macrosegregation. The increase in iron content in this area could be the reason for this. The interfacial zone has a microhardness of about 430 HV, and in the island macrosegregation, the microhardness increases to about 550 HV. Further research could involve an in-depth analysis of the phase and chemical composition, as well as examining other metals and alloys as interlayers.

Multi-materials can locally enhance the properties of products to improve their performance. In some cases, it might be necessary to improve the fracture toughness properties locally. This work is devoted to investigating the fracture toughness of multi-material Ti6Al4V/Cp-Ti specimens produced via laser powder bed fusion (L-PBF). The powder feeding and distributing system of the L-PBF machine was modified for programmable dual-powder feed capability. The multi-material Ti6Al4V/Cp-Ti samples analyzed in this work are layered materials, where the Ti6Al4V alloy serves as the base material and Cp-Ti is present as separate layers. Samples of this type rely on the principle of crack inhibition, where fracture energy is dissipated in the more ductile Cp-Ti layers. Two variants of alternating ductile layers were studied. The microstructure of the materials and interfacial zone were analyzed using an optical microscope. Chemical composition was examined with a scanning electron microscope. The size of the interfacial zone in the multi-material averaged between 250 and 300 μm. A comparison of the tensile tests results with the literature data (of relatively pure Ti6Al4V alloy) reveals that there is a minor reduction in ultimate tensile strength and elongation. The obtained results confirm the possibility of locally increasing fracture toughness through the creation of a multi-material structure using L-PBF.

This study examines the Inconel 718/Ti6Al4V multi-material with a Cu and Nb interlayer produced by SLM. To achieve this, it is necessary to investigate the microstructure, the chemical and phase composition, and the hardness of the interfacial zone in the multi-material samples. Furthermore, it is necessary to determine the impact of interlayer utilization on the mechanical properties of multi-material samples. The investigation showed that the formation of island macro-segregation was observed in all interfacial zones of the multi-material samples. The interfacial zones, Ti6Al4V/Nb and Cu/Inconel 718, exhibited a relatively sharp transition in the chemical composition. In contrast, the Cu/Nb interfacial zone exhibited a gradual transition. The results of the chemical composition study indicated that the width of the Nb/Cu transition zone was approximately 700 μm. No new phases were identified in the production of the multi-material samples. The typical phases were present in the alloy zone, as well as in the Nb/Cu interfacial zone. During the transition from the Ti6Al4V zone to the Inconel 718 zone through the Nb and Cu zones, the average microhardness values changed as follows: 270 → 190 → 120 → 300 HV. The ultimate tensile strength values for the multi-material samples reached 910 MPa.

The use of additive manufacturing to fabricate current collectors with increased surface area opens new opportunities for controlling electrode morphology, improving conductivity, and thereby boosting the overall performance of batteries. This can be achieved by increasing the contact area between the active mass and the current collector. This paper focuses on the investigation of 3D current collectors with an enhanced surface area for cathodes obtained by laser powder bed fusion. The quality and dimensional accuracy of the 3D current collector structures as well as the electrical characteristics and longevity of batteries were analyzed in this study. It has been demonstrated that the utilization of printing parameters comprising a laser power of 200 W, a scanning speed of 500 mm/s, and a hatch distance of 0.25 mm, with a layer thickness of 0.03 mm, results in a decrease in the number of defects in the 3D current collector. In the first cycle, the capacitance characteristics exhibited discharge capacities of 189.79 mAh/g for Al-f and 192.06 mAh/g for AlSi10Mg. The Coulomb efficiencies for the samples were 86 and 92.5%, respectively. Anisotropy of conductive properties arises during the printing process, which must be considered when designing the 3D current collectors, as it may have an impact on the capacitive and cyclic characteristics of the samples.

Selective laser melting (SLM) proves to be a suitable method for fabricating multi-material products, offering heightened performance. The objective of this study is to examine the mechanical properties of the VZh159–CuCr1Zr multi-material system produced through selective laser melting. We conducted tensile and compressive strength tests on these samples, followed by fractography, examination of polished sections, and a comparison of measured mechanical properties with existing data. Our findings are summarized as follows: the phase compositions in the regions of pure alloy denote solid solutions. X-ray diffraction (XRD) patterns of the interface zone reveal peaks corresponding to both alloys. The tensile strength of VZh159–CuCr1Zr multi-material samples, as measured in tensile tests, is σ_u = 430 ± 20 MPa, with a relative elongation of ε = 4.6 ± 0.3 %. Results from compressive strength tests show values of σ_u = 822 ± 23 MPa, and relative compression ε = 42.5 ± 1.5 %. Comparing these values with those of the pure CuCr1Zr alloy, the ultimate tensile strength is approximately 53 % higher (according to available data), while the conditional yield strength is about 80 % higher. Fractography of the VZh159–CuCr1Zr multi-material sample after tensile tests indicates that the interface zone exhibits both more ductile fracture features characteristic of the CuCr1Zr alloy (pits and a lack of a smooth surface) and less ductile features charac­teristic of the VZh159 alloy (microcracks). Examination of the polished section of a VZh159–CuCr1Zr multi-material sample after compressive strength tests reveals that the presence of a more ductile CuCr1Zr alloy in the interface zone contributes to arresting the crack, which propagates at a 45° angle to the direction of load application in the VZh159 alloy region.