Triply Periodic Minimal Surface Architectures Research Articles

Sandwich structures with TPMS core and printed circuit board faces

Sandwich structures are widely used in the aerospace industries due to their mechanical properties that give them high energy absorption, low density, and high mechanical strength. These structures are composed of two faces interspersed by a core that can have various geometric configurations. One of the most widely used geometric cells are honeycomb structures, highly used in structural applications since the early 20th century. However, new geometric core configurations, as well as alternative materials and manufacturing processes, are being studied for space applications. Triply Periodic Minimal Surfaces (TPMS) are lattice structures composed of periodic surface structures in three independent directions. Among the available models, the most notable TPMS structures are Schwartz-type, Diamond-type, and Gyroid-type. Since the structures are too complex to be manufactured by subtractive manufacturing, additive manufacturing is excellent, being able to produce complex structures much faster and easier. One of the most common types of 3D printing is Fused Deposition Modeling (FDM), which is based on the fusion and deposition of various materials, such as thermoplastic materials. To save space and improve the mechanical strength of Cubesats, sandwich structures are being produced using printed circuit boards (PCB) of electrical and electronic components as outer faces. These faces are called laminates and are made of thermosetting materials such as fiberglass and epoxy resin, composites, or ceramic materials. The objective of this paper is to produce sandwich panels, with a core based on the TPMS architecture. They will be printed in thermoplastic material with laminated faces used in printed circuit boards. A numerical analysis using the finite element method was performed and its testing according to ASTM C393, furthermore, this paper aims to realize an optimized TPMS core with mass distribution based on the stress profile and compare them.

Thermology-mechanical integrated SiC panel with triply periodic minimal surface architectures for thermal protection

In this study, a thermomechanically integrated SiC panel is fabricated using vat photopolymerization technology. A theoretical predictive model is developed for the thermodynamic integration of triply periodic minimal surfaces (TPMS). Firstly, a mathematical analysis model is established to integrate thermodynamics into TPMS architecture. Among the structures studied, the Schoen gyroid exhibits the best insulation performance, surpassing the Schwarz diamond, Neovius surface, and Schwarz W due to its superior radiation effect within the sandwich configuration's core structure. Regarding compression mechanical performance, the Schoen gyroid structure proved to be the optimal choice with yield points of 16.18 MPa and 9.8 MPa. The successful additive manufacturing of SiC ceramics with TPMS architectures is achieved by considering the integration of thermology and mechanics.

Combining multiple lattice-topology functional grading strategies for enhancing the dynamic compressive behavior of TPMS-based metamaterials

Recent developments in additive manufacturing technology have enabled the precise fabrication of intricate lattice materials, also known as metamaterials, for various engineering applications, particularly those involving dynamics. Lattice materials, consisting of sheet-based triply periodic minimal surface (TPMS) structures, have been extensively studied for their mechanical performance under quasi-static and dynamic loading conditions. However, less attention has been given to assessing the effect of grading the lattice topological properties for improved compression loading. Consequently, this paper investigates the effect of topology hybridization, periodicity gradation, cell compaction, and combining multiple functional grading strategies on the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. We conducted quasi-static compression tests to evaluate different regular sheet-based TPMS architectures and select the most promising candidates for topology-functional gradation. Subsequently, numerical simulations were performed to analyze the compressive deformation behavior and properties of functionally graded sheet-based TPMS lattice materials alongside the uniform topologies. This test showed that Schwartz Diamond (Du) and Face-centered Rhombic Dodecahedral (FRDu) lattice structures exhibit superior compressive properties in quasi-static conditions. Furthermore, simulations revealed that the lattice topology and grading strategy significantly influence the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. Specifically, the IWPu topology showed a notable increase in compressive strength and energy absorption compared to the other lattice types as the strain rate increased. Hybridizing Du and FRDu topologies produced a strictly layer-wise deformation pattern, resulting in improved quasi-static and dynamic compressive properties compared to the elementary topology. However, a superior uniaxial compressive modulus and strength were achieved by gradually adjusting the periodicity of a single topology (Du) while maintaining the same relative density. The combination of relative density and periodicity gradation led to more desirable deformation behavior while enhancing the overall compressive properties of the metamaterial, regardless of the strain rate.

Highly strain-rate sensitive and ductile composite materials combining soft with stiff TPMS polymer-based interpenetrating phases

The current work investigates the engineering of strain-rate sensitive and ductile composites through the combination of stiff, triply-periodic-minimal-surface (TPMS) with soft, rubber-type material phases. Different interpenetrating phase composite (IPC) designs are considered, with Diamond, Fisher-Koch, and IWP TPMS architectures as reinforcement phase topologies. The loading rate sensitivity of the arising IPCs is evaluated at different strain-rates, revealing an effective composite performance that well separates from the either brittle or substantially low-strength behavior of its constituent materials. Significant strain-rate effects are recorded, which relate to increased stiffness and energy absorption attributes upon substantial ductility, with the actual performance to depend on the underlying reinforcement phase topology. The effective strain-rate IPC constitutive response is well-captured by dedicated, low numerical cost and high accuracy machine learning models, whereas Digital Image Correlation (DIC) and finite element analysis are employed to provide insights in the inner strain and stress fields developed and failure modes observed. Overall, energy absorptions higher than 10 and up to 14 MJ m−3 are reported for strain-rates in the order of 100, furnishing specific energy absorptions (SEA) in the uppermost range of the effective composite material behaviors up to now reported, upon exceptionally high crushing force efficiencies (CFE) at moderate densities.

Mechanical properties of 3D printed interpenetrating phase composites with TPMS architectures

The mechanical performance of triply periodic minimal surface (TPMS)-based interpenetrating phase composites (IPCs) is investigated experimentally and numerically. The TPMS structures are employed as reinforcement phases to improve the mechanical properties of the composites which are fabricated using Polyjet multi-material additive manufacturing. Afterwards, the IPCs as well as their constituent empty phases are uniaxially compressed on a universal electronic machine to investigate the mechanical response and deformation modes. Experimental result shows that G-STPMS IPC outperforms other IPCs with the highest strength of 84 MPa and D-LTPMS IPC exhibits the best energy absorption performance with SEA of 24.6 J/g. The strength and SEA value of TPMS-based IPCs are superior to the sum of the two empty phases up to 497 % and 192 %, respectively. Furthermore, IPCs exhibit excellent damage resistance that abrupt failure or local shear is hardly observed during axial compression. Simulation result reveals the mechanism of the synergistic effect inside IPCs. Moreover, it is proved that the mechanical properties of the IPCs are influenced by the equivalent density. In general, the combination of high toughness and strength makes TPMS-based IPCs promising candidates for energy absorption.

The effects of sheet and network solid structures of similar TPMS scaffold architectures on permeability, wall shear stress, and velocity: A CFD analysis.

Triply periodic minimal surface (TPMS) is known mathematically as a surface with mean curvature of zero and replicated in three directions infinitely. Providing the pore combination in porous structures with surface connections, they provide large surface areas. This study aims to determine the effects of the network solid and sheet solid structures in the three different TPMS architectures on bone regeneration. Evaluation is made for Diamond, Gyroid, and I-WP structures, which are widely preferred architectures in terms of mechanical strength. Scaffolds are modeled as both network solid and sheet solid unit cells with similar porosities (60%, 70%, and 80%). Flow analyses are performed with the Computational Fluid Dynamics method to determine of potential for bone cell development of scaffolds. The permeability, wall shear stress on the surfaces, and the flow velocity distribution of the scaffolds are obtained with these analyses. The permeability value of 18 scaffolds is between the permeability values determined for trabecular bone. The permeability of network solid TPMS scaffolds for the same architectures is higher than sheet solid TPMS scaffolds due to the low pressures generated. The maximum wall shear stress in scaffolds decreases as porosity increases. Since the maximum wall shear stresses occur in less than 0.1% area on the scaffold surfaces, it is more appropriate to examine distribution of these stresses on the scaffold surfaces. Sheet solid structures within TPMS are more advantageous for biomechanical environments due to their greater surface area at similar porosities, wall shear stress, and permeability values.

Artificial neural network model of the mechanical behaviour of shape memory alloy Schwartz primitive lattice architectures

This work proposes a novel artificial neural network (ANN)-based framework to explore the mechanical behaviour of shape memory alloy (SMA) Schwartz primitive triply periodic minimal surfaces (TPMSs) architectures where a loop with multiple conditions (LMCs) is introduced into the framework to improve its accuracy. Remarkably, it is found that the introduced ANN-based framework comprehends extremely well the example data and then provides a highly accurate prediction for the topology-driven mechanical behaviour of the SMA TPMS lattice architectures, which do not belong to the example. Indeed, the mechanical responses obtained from ANN-based approach excellently agree with that from numerical homogenization, with the maximum percent difference below 2.7% attained when the TPMS is subjected to tension or shear during the loading and unloading processes. More interestingly, the ANN-based approach can perform well with the increment of relative density or temperature 1000 times smaller than that in the homogenization, only requiring a little simulation time or thousands of times faster than that in the homogenization at the same computer setup. Hence, the mechanical behaviour of SMA TPMSs can be accurately characterized by the proposed framework at almost any value of the relative density or the temperature after the training. Subsequently, the ANN-based framework is used to map two-dimensionally the impact of varying relative density, temperature, and deformation on the effective hardness and superelasticity of the SMA TPMS architectures. The results show that the superelasticity of SMA TPMS scaffolds increases with decreased temperature and relative density and with increased deformation, in a nonlinear pattern. This work lays the foundation for further research on using ANN to explore the mechanical response and advanced applications of the complex SMA-based structures, such as smart composite systems, helical springs, and metamaterials at considerably reduced computational and financial costs.

Modelling of functionally graded triply periodic minimal surface (FG-TPMS) plates

Functionally graded porous plates have been validated as remarkable lightweight structures with excellent mechanical characteristics and numerous applications. With inspiration from the high strength-to-volume ratio of triply periodic minimal surface (TPMS) structures, a new model of porous plates, which is called a functionally graded TPMS (FG-TPMS) plate, is investigated in this paper. Three TPMS architectures including Primitive (P), Gyroid (G), and wrapped package-graph (IWP) with different graded functions are presented. To predict the mechanical responses, a new fitting technique based on a two-phase piece-wise function is employed to evaluate the effective moduli of TPMS structures, including elastic modulus, shear modulus, and bulk modulus. In addition, this function corresponds to the cellular structure formulation in the context of relative density. The separated phases of the function are divided by the different deformation behaviours. Furthermore, another crucial mechanical property of porous structure, i.e, Poisson’s ratio, is also achieved by a similar fitting technique. To verify the mechanical characteristics of the FG-TPMS plate, the generalized displacement field is modelled by a seventh-order shear deformation theory (SeSDT). A NURBS-based isogeometric analysis (IGA) is then employed to capture the C1 continuity in approximations. Numerical examples regarding static, buckling, and free vibration analyses of FG-TPMS plates are illustrated to confirm the reliability and accuracy of the proposed approach. The influences of various porosity distributions, average relative densities, thickness-to-length ratios, aspect ratios, and boundary conditions on the plate responses are achieved. Consequently, these FG-TPMS structures can provide much higher stiffness than the same-weight isotropic plate. The greater stiffness-to-weight ratio of these porous plates compared to the full-weight isotropic ones should be considered the most remarkable feature. Thus, these complex porous structures have numerous practical applications because of these high ratios and their fabrication ability through additive manufacturing (AM) technology.

Deep learning-based inverse design framework for property targeted novel architectured interpenetrating phase composites

Interpenetrating phase composites (IPCs) are advanced multi-phase composites where each phase forms an entirely interconnected network leading to enhanced performance. This paper introduces a novel inverse design approach, wherein mathematically-known triply periodic minimal surfaces (TPMS) representations are combined with a deep neural network-based approach for generating IPCs with specified properties. The proposed approach utilizes a weighted combination of Schwartz P, Diamond D, and Schoen’s F-RD TPMS architectures to generate novel IPCs. Additionally, we outline a novel deep learning-based computational approach that predicts combinatorial TPMS-based IPCs for targeted effective elastic properties. Specifically, a five-layer deep neural network (DNN) that enables inverse mapping between five different material properties and six geometrical parameters defining the TPMS-based IPCs is outlined. It is also empirically shown that DNN accurately predicts combinatorial TPMS-based IPCs at a fraction of the computational cost and hence, can play a vital role in multiscale design problems and find extensive usage in IPCs design problems. The effective elastic properties (Young’s modulus, Poisson’s ratio, bulk modulus, and shear modulus) of proposed generative TPMS-based IPCs are evaluated using the finite element method and are compared against a single phase TPMS-based IPCs, analytical models, and elastic bounds. Numerical results demonstrate that IPCs generated by the proposed method shows superior mechanical behavior.

Mechanical-electromagnetic integration design of Al[formula omitted]/SiO[formula omitted] ceramic cellular materials fabricated by digital light processing

Mechanical-electromagnetic integrated design has great potential in the development of electromagnetic shielding equipment for military use. In this study, Al2O3/SiO 2 ceramics with triply periodic minimal surfaces (TPMSs) were fabricated using digital light processing (DLP) technology. The preparation of SiO 2 and Al2O3 powders is vital for DLP because minimal aggregates or sedimentation in the ceramic paste is required. Debinding and sintering programs were developed to prevent defects in the designed microstructure. The interfacial characterization demonstrated that the surfaces of the sintered ceramics were compact and smooth. The compression strength of the TPMS ceramic with a volume fraction of 50% was 24 MPa, which is relatively good among additively manufactured cellular ceramics. The TPMS structures also exhibited significant electromagnetic interference (EMI) shielding effectiveness in the X-band (2 to 18 GHz), and the shielding performance was adequate to meet the demands of electromagnetic shielding materials. Additive manufacturing of Al2O3/SiO2 ceramic with TPMS architectures was successfully achieved by considering the mechanical-electromagnetic integration.

On the computational modeling, additive manufacturing, and testing of tube-networks TPMS-based graphene lattices and characterizing their multifunctional properties

Lattices based on triply periodic minimal surfaces (TPMSs), which have been receiving increasing interest due to advances in additive manufacturing, are known now to be outperforming other cellular materials in several properties, enabling wider multifunctional applications. In this work, we focus on fabricating graphene TPMS lattices, viz., Gyroid, Schoen's I-WP (IWP), and Diamond, and investigate their multifunctional properties experimentally and computationally. The three-dimensional (3D) graphene structures were synthesized using a self-assembly hydrothermal-assisted dip-coating technique and the resulting lattices were tested for their mechanical, thermal, and electrical properties and compared to finite element simulation results. The graphene TPMS lattices resulting from the fabrication take the topology of a new class of TPMS architectures that are referred to here as the TPMS tube-networks. IWP demonstrated the highest elastic modulus as well as electrical and thermal conductivities. This study shows that 3D porous tube graphene can be utilized in designing new lightweight structural materials of low density with controllable thermal and electrical properties and mechanical strength with a potential to be employed in multifunctional engineering applications.

Effective compressive behavior of functionally graded TPMS titanium implants with ingrown cortical or trabecular bone

This work investigates numerically the effect of gradient coefficient, partial ingrowth length of bone, topology, loading direction, and average relative density on the yield strength (YS) and effective stiffness of functionally graded (FG) triply periodic minimal surface (TPMS)-based titanium implant topologically interconnected with ingrown bone subjected to uniaxial compression. The partially or fully topologic interconnection of two bi-continuous phases including titanium TPMS and bone forms a partially or fully interpenetrating phase composites (IPCs), for which their effective mechanical response is determined by means of finite element analysis and computational homogenization. The numerical framework used for this purpose is conceptually validated against the experimental characterization of the effective mechanical properties of additively manufactured two-phase FG IPC samples consisting of a white Polylactic Acid (PLA)-based reinforcement phase and white porous Polyvinyl Alcohol Natural (PVA)-based matrix phase under the same conditions such as the topology, dimensions, boundary conditions, and material property. The results show that the effective yield strength of the titanium-bone IPC increases with the decreased absolute value of the gradient coefficient regardless of the loading direction. Comparison between homogenization results obtained using titanium implant TPMS architectures with gyroid, primitive, diamond, and IWP shows that IWP exhibits the highest effective yield strength for a given porosity level. Moreover, the effective yield strength of the bone-implant FG IPCs increases with a rise of partial ingrowth length of bone and higher average relative density of the implant. The effective yield strength is also found to be substantially dependent on the direction of the applied load.

Low elastic modulus and highly porous triply periodic minimal surfaces architectured implant for orthopedic applications

A mismatch between the implant and interacting bone Young's modulus causes stress shielding phenomena, which leads to instability of the implant and early failure. This paper focuses on the development of medical-grade titanium alloy (Ti6Al4V)-based metallic highly porous structure to mitigate the stress shielding effect. In this study, we propose an effective method to generate a highly porous implant based on triply periodic minimal surfaces (TPMS) architecture. Three-dimensional models of different TPMS architectures such as Diamond, Gyroid, I-graph-Wrapped Package graph (IWP), and Primitive were constructed with a 2 × 2 × 2 mm lattice size and unit cell size of 1 mm. Mechanical testing of the finite-element models was performed under static loading conditions to evaluate the effective elastic modulus ( Eeff) of each porous architecture. It was found that the primitive structure exhibits the lowest Eeff, whereas the Gyroid exhibits the highest Eeff, results indicate that porous architecture reduces Eeff by more than 95%, thereby reducing the stress shielding effect. Moreover, pore size and surface-area-to-volume ratio (SA/V ratio) were also investigated. Findings suggested that the primitive structure has the highest pore size, which will be suitable for enhanced bone ingrowth. A high SA/V ratio in IWP offers the possibility of enhanced cell adhesion, migration, and proliferation.

Mechanical and fluid characteristics of triply periodic minimal surface bone scaffolds under various functionally graded strategies

Abstract A laser powder bed fusion additive manufacturing has enabled the fabrication of triply periodic minimal surface (TPMS). These structures are widely acknowledged for their suitability in bone implant applications. Nevertheless, although it is essential for TPMS-based implants to exhibit graded features to mimic those of natural bones for desirable functionality, the effect of graded features on mechanical properties, flow behavior, and geometrical morphologies requires further clarification. As a result, this study carried out a comprehensive numerical and experimental assessment on the impact of graded IWP structures on the effective elastic modulus, Gaussian curvature, permeability, and fluid-induced wall shear stress. Among various TPMS architectures, the IWP structure was chosen to be explored in this work owing to its favorable physical responses for bone tissue ingrowth as reported in the literature. Overall, we found that the grading features had a considerable impact on the global response such as the effective modulus and fluid permeability. However, the local response such as Gaussian curvatures and fluid-induced wall shear stress was significantly less affected.

Selective Laser Melting Fabrication of Porous Ti6Al4V Scaffolds With Triply Periodic Minimal Surface Architectures: Structural Features, Cytocompatibility, and Osteogenesis.

The relationship between pore architecture and structure performance needs to be explored, as well as confirm the optimized porous structure. Because of the linear correlation between constant C and pore architecture, triply periodic minimal surface (TPMS) based porous structures could be a controllable model for the investigation of the optimized porous structure. In the present work, three types of TPMS porous scaffolds (S, D and G) combined with four constants (0.0, 0.2, 0.4 and 0.6) were designed, and built successfully via the selective laser melting (SLM) technology. The designed feature and mechanical property of porous scaffolds were investigated through mathematical method and compression test. And the manufactured samples were co-cultured with rMSCs for the compatibility study. The results indicated that the whole manufacturing procedure was good in controllability, repeatability, and accuracy. The linear correlation between the porosity of TPMS porous scaffolds and the constant C in equations was established. The different TPMS porous scaffolds possess the disparate feature in structure, mechanical property and cell compatibility. Comprehensive consideration of the structure features, mechanical property and biology performance, different TPMS structures should be applied in appropriate field. The results could guide the feasibility of apply the different TPMS architectures into the different part of orthopedic implants.

Effective stiffness, strength, buckling and anisotropy of foams based on nine unique triple periodic minimal surfaces

Recent advancements in the field of additive manufacturing has led to an increased interest in the study of cellular architectures especially triply periodic minimal surfaces (TPMS) and their properties. In this study, 9 sheet-based TPMS architectures are studied by comparing their effective stiffness, strength, buckling and anisotropic properties. The TPMS lattices are generated using level set equations where the relative density of each lattice is varied to study the effective properties as a function of relative density. Finite element models of these lattices are built to study the elastic and plastic deformation behaviour under uniaxial, shear, hydrostatic and buckling loading conditions. Effective properties such as Young’s modulus, shear modulus, bulk modulus, Poisson’s ratio and strengths under uniaxial, shear, hydrostatic and buckling loading are computed against each other and other common lattice structures. In addition, anisotropic behaviour as well as the orientation dependence of the properties of each lattice are also studied. The geometric efficiency criterion is predominantly used to evaluate the different structures and the results obtained are consolidated in both quantitative and qualitative manner. SC lattice outperforms all the other lattices in terms of strength and stiffness efficiencies at lower and higher relative densities. On the other hand, I2 − Y** lattice shows the weakest stiffness and strength efficiency especially at higher relative densities. The current study focuses on the properties of some unique lattice architectures that have not been studied previously and shows promising efficiencies compared to the common architectures studied such as the Gyroid lattice. This study opens the door for employing these lattices in various applications and the results are very useful to multi-scale topology-optimization studies.

Thermal characterization of 3D-Printed lattices based on triply periodic minimal surfaces embedded with organic phase change material

Owing to their high latent heat of fusion and thermal stability, organic phase change materials (PCMs) are lucrative candidates for utilization in latent heat thermal energy storage systems (LHTES). However, since their low thermal conductivity inhibits their direct usage in such systems, they are often impregnated into a thermally conductive metallic matrix, which exhibits an effective thermal conductivity superior to that of PCM alone. In this study, metallic lattices based on Triply periodic minimal surfaces (TPMSs) are utilized as thermal conductivity enhancers for organic PCMs. TPMS are a class of periodic cellular materials that have been recently studied in several structural, thermo-mechanical, and other applications showing promising performance. However, their utilization with PCM in LHTES systems is a relatively uncharted area of research. Using selective laser sintering technique; four metallic TPMS structures were fabricated, i.e., diamond, gyroid, I-graph and wrapped package-graph (IWP), and primitive, and were later impregnated with two organic PCMs (i.e., RT62HC and RT64HC). The thermal conductivity of both PCMs and TPMS-PCM composite were measured using Transient Plane Source (TPS) method. It was found that the TPMS structures enhanced the thermal conductivity of the PCMs. Moreover, for a fixed porosity and unit cell size, the effective thermal conductivity was found to be a function of the TPMS architecture. A preliminary numerical analysis to compare the heat performance of PCM-alone and PCM embedded with TPMS (primitive) showed clear superiority of the TPMS-PCM composite over the PCM-alone case. Therefore, the utilization of TPMS structures in LHTES could be promising in a bid to increase the performance of organic PCMs.

Hierarchical sheet triply periodic minimal surface lattices: Design, geometric and mechanical performance

Lattices with hierarchical architectures exhibit unique geometric and mechanical properties compared with single scale ones. While numerous research efforts have focused on hierarchical strut lattices, hierarchical sheet lattices have yet to be studied in detail. This paper proposes a systemic framework including geometric design, finite element modelling, additive manufacturing, and mechanical testing for hierarchical sheet triply periodic minimal surface (TPMS) lattices such that the lattice walls comprise successively smaller scale TPMS architectures. Geometric properties including relative densities and volume-specific surface areas of hierarchical lattices are analytically calculated and verified via numerical calculations. The compressive properties of 2-order sheet Gyroid lattices are investigated with finite element simulations and experimentally validated using micro-selective laser melting fabricated stainless-steel specimens. Geometric analysis shows that hierarchical sheet lattices have great potential to achieve a wide range of controllable geometric properties including hierarchical porosities, ultralow densities, and significantly enlarged surface areas. Simulation results indicate that 2-order lattices have superior buckling strength over single scale lattices at ultralow densities. At moderate densities, 2-order lattices exhibit reduced modulus and strength, but more stable failure behaviour. With these unique combinations of geometric and mechanical properties, hierarchical sheet TPMS designs are shown to be desirable structural configurations for biomedical scaffolds.

In vitro evaluation of electrochemically bioactivated Ti6Al4V 3D porous scaffolds

Triply periodic minimal surfaces (TPMS) are known for their advanced mechanical properties and are wrinkle-free with a smooth local topology. These surfaces provide suitable conditions for cell attachment and proliferation. In this study, the in vitro osteoinductive and antibacterial properties of scaffolds with different minimal pore diameters and architectures were investigated. For the first time, scaffolds with TPMS architecture were treated electrochemically by plasma electrolytic oxidation (PEO) with and without silver nanoparticles (AgNPs) to enhance the surface bioactivity. It was found that the scaffold architecture had a greater impact on the osteoblast cell activity than the pore size. Through control of the architecture type, the collagen production by osteoblast cells increased by 18.9% and by 43.0% in the case of additional surface PEO bioactivation. The manufactured scaffolds demonstrated an extremely low quasi-elastic modulus (comparable with trabecular and cortical bone), which was 5–10 times lower than that of bulk titanium (6.4–11.4 GPa vs 100–105 GPa). The AgNPs provided antibacterial properties against both gram-positive and gram-negative bacteria and had no significant impact on the osteoblast cell growth. Complex experimental results show the in vitro effectiveness of the PEO-modified TPMS architecture, which could positively impact the clinical applications of porous bioactive implants.

Corrosion Resistance of the CpTi G2 Cellular Lattice with TPMS Architecture for Gas Diffusion Electrodes.

The corrosion of materials used in the design of metal-air batteries may shorten their cycle life. Therefore, metal-based materials with enhanced electrochemical stability have attracted much attention. The purpose of this work was to determine the corrosion resistance of commercially pure titanium Grade 2 (CpTi G2) cellular lattice with the triply periodic minimal surfaces (TPMS) architecture of G80, D80, I-2Y80 in 0.1 M KOH solution saturated with oxygen at 25 °C. To produce CpTi G2 cellular lattices, selective laser melting technology was used which allowed us to obtain 3D cellular lattice structures with a controlled total porosity of 80%. For comparison, the bulk electrode was also investigated. SEM examination and statistical analysis of the surface topography maps of the CpTi G2 cellular lattices with the TPMS architecture revealed much more complex surface morphology compared to the bulk CpTi SLM. Corrosion resistance tests of the obtained materials were conducted using open circuit potential method, Tafel curves, anodic polarization curves, and electrochemical impedance spectroscopy. The highest corrosion resistance and the lowest material consumption per year were revealed for the CpTi G2 cellular lattice with TPMS architecture of G80, which can be proposed as promising material with increased corrosion resistance for gas diffusion in alkaline metal-air batteries.