Good Machinability Research Articles

DFT based comparative analysis of the physical properties of some binary transition metal carbides XC (X = Nb, Ta, Ti)

Binary metallic carbides belong to technologically prominent class of compounds. Present work theoretically explores the structural, mechanical, optoelectronic, and some thermal properties of XC (X = Nb, Ta, Ti) compounds using the density functional methodology. A number of the results obtained are novel. The computed elastic constants and moduli disclose that the compounds possess moderate elastic anisotropy and reasonably good machinability (machinability index above 1.45 for all the compounds), mixed bonding characteristics, high Vickers hardness (in the range 19–25 GPa) with very high Debye temperatures (in the range 800–925 K) and brittle characteristics. The elastic/structural stability conditions are fulfilled for all the carbides under study. The Young's modulus and bulk modulus of TiC are lower than those of NbC and TaC. All the XC (X = Nb, Ta, Ti) compounds are hard and suitable for heavy duty structural applications. The electronic band structures show finite density of states at the Fermi level revealing metallic character of the XC (X = Nb, Ta, Ti) compounds. Mixed bonding features are evident from the charge density distribution maps of the XC (X = Nb, Ta, Ti) compounds. The lattice dynamical properties, such as the phonon dispersion curves and phonon density of states for XC (X = Nb, Ta, Ti) are investigated. Absence of negative phonon modes in the Brillouin zone indicates that the carbides under study are dynamically stable. The energy dependent optical constants are nearly isotropic. The optical absorption, reflectivity spectra, and the high value of the low energy index of refraction of XC (X = Nb, Ta, Ti) compounds reveal that they hold promise to be utilized in optoelectronics. The computed melting temperature, lattice thermal conductivity, Debye temperature, and minimum phonon thermal conductivity of the XC (X = Nb, Ta, Ti) compounds exhibit conformity with the computed elastic and bonding characteristics. Extremely high melting point (4399 K) of the compound TaC suggests that it is a very good candidate for applications at high-temperatures.

A novel thermally matched conductive phase of silicon nitride ceramics

Tungsten was first proposed as a conductive phase that better matches the thermal expansion of silicon nitride ceramics. Silicon nitride ceramics containing 20 vol% tungsten particles were fully densified via gas pressure sintering under a following nitrogen atmosphere. After introducing the tungsten particles, the thermal conductivity is increased two-fold and thermal expansion coefficient (CTE) almost remains as low as the monolithic silicon nitride ceramics. Most importantly, the composite ceramics achieve good electrical conductivity and a small and complex shape was machined via wire-electrode cutting to confirm its good wire-electrical discharge machinability. Tungsten particles have been proven to be a new ideal conductive phase for silicon nitride ceramics, and a new wire-electrical discharge machinable silicon nitride-based ceramic was prepared.

Machinability analysis of carbon fibre reinforced PET-Glycol composites processed by additive manufacturing

Fused filament fabrication (FFF) is one of the most widely used additive manufacturing (AM) techniques, which has enabled a simpler, more flexible, and low-cost processing procedure for obtaining functional fibre reinforced composite products. However, one of the shortcomings of AM processing is its poor geometric and dimensional behaviour that hinders the manufacture of high-quality functional parts. Though this limitation can be overcome with surface post-processing machining, the machining of composites is complex due to their non-homogeneous microstructure producing delamination, splintering, and fractures. In this study, the machinability of short carbon fibre reinforced glycol-modified polyethylene terephthalate (CF-PETG) processed by FFF additive manufacturing was assessed in face milling and edging peripheral milling operations by analysing the AM process parameters layer thickness (Lt) and build orientation (Bo). This machinability analysis was based on energy consumption and geometric properties. The former was assessed by measuring cutting forces, and the latter involved examining dimensional accuracy, flatness and surface roughness measurements, combined with 3D-topography and SEM microscope images. PETG processed by FFF showed good machinability in both machining operations with acceptable energy consumption and surface texture, with no significant effect of Lt or Bo. The addition of carbon fibre reinforcement to PETG improved energy consumption in both operations, and enhanced the surface texture in face milling. However, machinability worsened in terms of geometric properties for peripheral milling with the addition of carbon fibre and increased Lt, exhibiting substantial surface defects such as tearing and burrs.

Effects of Mn content on austenite stability and mechanical properties of low Ni alumina-forming austenitic heat-resistant steel: a first-principles study

Low Ni alumina-forming austenitic (AFA) heat-resistant steel is an advanced high-temperature stainless steel with reduced cost, good machinability, high-temperature creep strength, and high-temperature corrosion resistance. Using the First-principles approach, this study examined the effect of Mn content on austenite stability and mechanical properties at the atomic level. Adding Mn to low Ni-AFA steel increases the unit cell volume with an accompanying increase in the absolute value of formation energy; the austenite formed more easily. The austenitic matrix binding energy decreases and remains negative, indicating austenite stability. As the Mn content increases from 3.2 to 12.8 wt%, the system's bulk modulus (B) rises significantly, and the shear modulus (G) falls. In addition, the system's strength and hardness decrease, and the Poisson ratio of the austenite matrix increases with improved elasticity; the system has excellent plasticity with an increase in the B/G. For the Fe22–Cr5–Ni3–Al2 system, with the increase of Mn content, the electron density distribution between the atoms is relatively uniform, and the electrons around the Mn atoms are slightly sparse, which will slightly reduce the structural stability of the matrix. The experiment demonstrated the matrix maintains the austenitic structure when adding 3.2–12.8 wt% Mn elements to low Ni-AFA steel. At an Mn content of 8 wt%, the overall mechanical properties of the high-Mn AFA steel are optimal, with a tensile strength of 581.64 MPa, a hardness of 186.17 HV, and an elongation of 39%.

Molecular dynamics simulation of phase transformation and wear behavior of Ni35Al30Co35 high temperature shape memory alloy

Ni–Al–Co alloys as one of the ferromagnetic high-temperature shape memory alloys (HTSMA) are attractive in aerospace and defense applications, due to their high phase transition temperature range (400–700K), high recoverable strain and good machinability. However, the underlying physics for the phase transformation behavior of β single-phase and β+γ two-phase Ni–Al–Co ternary alloys remain unclear. In this work, molecular dynamics simulation of phase transition, pseudoelasticity (PE) and wear behavior of Ni35Al30Co35 alloy were analyzed using the EAM potential. It shows that Ni35Al30Co35 alloy has a high martensite start temperature of 825K and an austenite start temperature of 631K, respectively. After five thermal cycles, martensite and austenite start and finish temperatures are stable around 500K and 700K. The initial structure of Ni35Al30Co35 alloy at 1000K is identified as BCC (β phase) and FCC (γ phase) structure, transforming to L10 structure through martensitic transformation. Furthermore, PE of Ni35Al30Co35 alloy exhibits about a 9.1% recoverable strain under <001> oriented uniaxial tension tests and about a 6.6% recoverable strain under <001> oriented uniaxial compression tests at a temperature of 1200K, showing the potential used in extreme environment. Moreover, spherical indenters with a radius of 15 Å were used to investigate the wear behavior of Ni35Al30Co35 alloy under different temperature. It was found that the PE effect affects the frictional behavior during nano-scratching. Combining the effect of high temperature softening and phase transition PE, the wear rate increases nearly by 5.3% when the temperature rises from 300K to 1000K. Furthermore, the friction force curve obtained is consistent with the friction force curve obtained by simulation at 300K.

Improved corrosion resistance of ZrO2/MgO coating for magnesium alloys by manipulating the pore structure

Magnesium (Mg) alloys are popular among structural materials due to their high specific strength and good machinability. However, poor corrosion resistance limits its application in harsh environments, which requires ceramic coating to overcome the shortage of corrosion sensitivity. In this work, ZrO2/MgO ceramic coating was in situ synthesized by plasma electrolytic oxide (PEO) technology, coatings with different pore structures were fabricated by adjusting the pH of the electrolyte, and X-ray computed tomography (XCT) is used to quantitatively investigate the pore structure in ceramic coating. As the pH of the electrolyte increases from 3 to 12, the Zr(OH)4 colloidal particles from electropositive to electronegative charges. Electropositive Zr(OH)4 moves to the anode by diffusion, while electronegative Zr(OH)4 participates in the growth of the coating by electromigration. Due to the electromigration mode at pH = 12, the ZrO2 deposited around the pores caused a change in the pore structure from interconnected to isolated, which resulted in a reduction of the overall porosity to 8.06%. Isolated pores effectively prevent the penetration of corrosive media, resulting in the corrosion current density (icorr) being nearly 46 times lower than the coating with pH = 3. This study presents a novel strategy of adjusting pore structure to enhance the corrosion resistance of ZrO2 ceramic coating, which may have implications for various applications.

Preparation of Macroscopic Low-Density Gold Foams with Good Machinability

Uniform, macroscopic monoliths (ranging from a few millimeters to a centimeter) of low-density gold foams with ~95% porosity and ~10-μm-diameter pores were prepared by the casting of gold-coated polystyrene core-shell particles followed by the thermal removal of the polymer core. The Au foams were composed of unique hollow gold spheres and showed superior mechanical integrity and resilience compared to the foams we previously reported. Highly efficient seeding and electroless gold-plating methods in this study caused a significant morphological transition in the gold coatings from coarse particles to fine particles, and finally, to a continuous layer. A modified, scalable casting approach to form large uniform monoliths (up to ~1-cm diameter) and a gentle baking condition to minimize undesirable densification of the final foams enabled us to develop a simple, efficient synthetic route to nanostructured macroscopic low-density gold foams. To demonstrate the improved mechanical stability and machinability, a representative monolithic Au foam (~0.9 g/cm3) was carefully cut into the hollow cylinder of gold foams by a series of machining and processing steps. Finally, we tried to understand the unique mechanical behaviors and properties of this gold foam by nanoindentation measurement.

Microstructure and properties characterization of laser-cladded Cu[sbnd]Al alloy coatings on Mg[sbnd]Li alloy

MgLi alloys have a wide application in the lightweight structure materials on account of their ultra-light-weight, good machinability and high specific strength. However, the low strength, insufficient wear and corrosion resistances of MgLi alloys have become a critical problem that hinders their applications. In order to achieve excellent wear and corrosion properties, LC-Cu3Al, LC-Cu6Al and LC-Cu9Al coatings are designed and prepared on MgLi alloy substrates in this study. The phase structure, microstructure, hardness, wear and corrosion properties of CuAl alloy coatings are investigated in detail. The results show that a good metallurgical bond is achieved between the CuAl alloy coatings and the substrates. LC-Cu6Al coating's hardness, wear and corrosion properties are the best. Compared with the MgLi alloy substrate, the average hardness of LC-Cu6Al coating increases by 6.75 times, while the wear volume decreases by 88.32 % and the corrosion current density decreases by two orders of magnitude. The results suggest that using laser cladding CuAl alloy coatings is an excellent strategy to enhance the surface properties of MgLi alloy.

L. KLEIN BRONZE 3444

Abstract L. Klein Bronze 3444 is a wrought copper-tin-lead-zinc-phosphorus alloy. The addition of tin increases its corrosion resistance and strength, while the addition of phosphorous increases wear resistance and stiffness. L. Klein Bronze 3444 combines high strength and fatigue resistance with high wear resistance, good machinability, and good corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-939. Producer or source: L. Klein SA.

Mineral composites: stay-in-place formwork for concrete using foam 3D printing

Optimizing the shape of concrete construction elements is significant in reducing their material consumption and total weight while improving their functional performance. However, the resulting non-standard geometries are difficult and wasteful to fabricate with conventional formwork strategies. This paper presents the novel fabrication method of mineral foam 3D printing (F3DP) of bespoke lost formwork for non-standard, material-efficient, lightweight concrete elements. Many innovative formwork studies have shown that stay-in-place formwork can help to reduce waste and material consumption while adding functionality to building components. Foams are particularly suitable for this application because of their high strength-to-weight ratio, thermal resistance, and good machinability. F3DP allows the waste-free production of geometrically complex formwork elements without long lead times and production-specific tooling. This paper presents the material system and robotic F3DP setup with two experimental case studies: a perforated facade panel and an arched beam slab. Both cases use concrete as structural material and strategically placed custom-printed foam elements. In this first preliminary study, concrete savings of up to 50% and weight reduction of more than 60% could be achieved. This is competitive with standardized solutions such as hollow-core slabs but, in contrast, allows also for non-standard element geometries. Additional functionality, such as programmed perforation, acoustic absorption, and thermal insulation, could be added through the stay-in-place formwork. Moreover, the challenges and future developments of F3DP for sustainable building processes are discussed. Further studies are required to verify the findings. However, considering the urgent need for resource-efficient, low embodied-carbon solutions in the construction industry, this work is an important contribution to the next generation of high-performance building components.

First-principles approach to the structural, physical, electronic, magnetic and optical properties of honeycomb ordered antimonates Na3Fe2SbO6

The search for new magnetic materials, electrochemical sensors and storage devices has ignited the study of layered honeycomb oxides in the past few years. We have performed a first-principles density functional theory (DFT) based investigation on the structural, elastic and associated thermophysical, mechanical, electronic, and optical properties of Na3Fe2SbO6 honeycomb ordered antimonates. The obtained lattice parameters as well as volume of the geometrically optimized structure were consistent with the available experimental data in the circumstance of ferromagnetic ordering. A comprehensive study of elastic constants implies a low to intermediate level of structure anisotropy, good machinability, mechanically brittle and hard. A large Debye temperature of 442.567 K and melting temperature of 2061.88 ± 300K implies high temperature application. The density of states suggests that the compound possesses a metallic character with a high magnetic moment. Furthermore, Na3Fe2SbO6 possesses excellent absorption characteristics in the spectral range in ultraviolet regions. It has low reflectivity and a high refractive index in the visible range of photon energy, and the plasmon peak found at 17.65 eV. The frequency-dependent optical conductivity confirms a metallic feature and agrees with the electronic density of states observations.

Optimization of DEFORM-3D simulated drilling of UNSS31603-steel by integrated MOORA coupled PCA technique

Due to its creep and stress-rapture strengths, superior formability, and high temperature tensile, UNS S31603 alloys are regarded as a good machinability material. As a result of the increased heat and thrust force generated by the cutting process, increased tool wear and damage are an inevitable byproduct of increased cutting speed and feed rate at the cutting edge. Drilling parameters are the only variable that can be changed to affect the temperature, and hence the wear and tear on the drill bit. In this inquiry, a 3D FEM has been proposed to study the drilling process simulation of UNS S31603 to reduce the drilling temperature, thrust force and drilling time. With DEFORM, a computer simulation model has been run to examine temperature changes as a function of cutting speed and feed rate. This study found that raising either the feed rate or the cutting speed resulted in a corresponding rise in temperature. With the aid of the unique optimization approach, integrated MOORA coupled PCA, the input process variables have been optimized. From the optimization, the optimized input parameters were identified as 260 rpm speed, 1.2 mm/min feed rate and the drill point angle of 90 degrees in order to achieve the minimum cutting force of 312 N and minimum temperature of 540 °C. At long last, optimal findings have been obtained that can assist cut down on the excessive development of heat, thrust force, and drilling time.

Influence of advanced coated tools on surface integrity characteristics of Nimonic C263

Advanced coated tool and cooling techniques were used for trial on Ni-based superalloy Nimonic C 263 to improve surface integrity, such as a white layer, grain refinement, and surface defect. Toolmaker microscope, Field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) system were employed to characterize the tool after machining, machined surface, and subsurface alteration. A possible cause of tool failure at high cutting speed and feed was severe plastic deformation and chipping of the cutting edge and nose, abrasive nose and flank wear, and the formation of a built-up layer (BUL). The white layer, surface defect, and grain refinement are always found less on machined surfaces with the PVD-coated tool under dry machining than with an uncoated tool under wet machining at a high rate. TiN/TiAlN multilayer coated WC tool can be suggested for good machinability and surface integrity in a sustainable, eco-friendly way to the industry for machining Nimonic C-263. MQL and flood mode cooling are also preferred at a cutting speed near 84 m/minute and a feed rate of 0.14 mm/rev.

A comparative study of the structural, elastic, thermophysical, and optoelectronic properties of CaZn2X2 (X = N, P, As) semiconductors via ab-initio approach

We present a detailed density functional theory (DFT) based calculations of the structural, elastic, lattice dynamical, thermophysical, and optoelectronic properties of ternary semiconductors CaZn2X2 (X = N, P, As) in this paper. The obtained lattice parameters are in excellent agreement with the experimental values and other theoretical findings. The elastic constants are calculated. The computed elastic constants satisfy the mechanical stability criteria. Moreover, large numbers of thermophysical parameters of these compounds are estimated, including the Debye temperature, average sound velocity, melting temperature, heat capacity, lattice thermal conductivity, etc. The comprehensive analysis of the elastic constants and moduli show that CaZn2X2 (X = N, P, As) compounds possess reasonably good machinability, strongly X-dependent Debye temperature and high Vickers hardness. The phonon dispersion curves and phonon density of states are investigated for the first time for the compounds CaZn2P2 and CaZn2As2. It is observed from the phonon dispersion curves that the bulk CaZn2X2 (X = N, P, As) compounds are dynamically stable in the ground state. Electronic properties have been studied through the band structures and electronic energy density of states. HSE06 (hybrid) functional is used to estimate the band gaps accurately. The electronic band structures show that CaZn2N2 and CaZn2As2 possess direct band gaps while the compound CaZn2P2 has an indirect band gap. The bonding characters of CaZn2X2 (X = N, P, As) compounds are investigated. We have thoroughly discussed the reflectivity, absorption coefficient, refractive index, dielectric function, optical conductivity and loss function of these semiconductors. The optical absorption, reflectivity spectra and the refractive index of CaZn2X2 (X = N, P, As) show that they hold promise to be used in optoelectronic devices.

Preliminary DOE Analysis of the Polishing Process of AISI P20 Mould Steel by Ultrasonic Erosion, Using Alumina and Diamond Hard Particles

The present work examines the surface finishing of AISI P20 tool steel, average hardness of 31.5 HRc, in the polishing process by ultrasonic erosion by loose abrasive particles. The study was performed in laboratory equipment, using various alumina and diamond hard particle sizes, ultrasonic frequencies and times. P20 steel is widely employed in the fabrication of polymer injection mould cavities due to its good machinability, homogeneous microstructure, hardness, corrosion and abrasion wear resistance. Mould cavity polishing processes represents the second longest manufacturing process time required to achieve the mould surface finish for good quality polymer parts. This time-consuming and largely artisanal polishing process contributes to high mould costs. Thus, several studies have been carried out in the literature to automate the mould polishing process, aiming to reducing surface roughness and polishing time. Present investigation was carried out in a surface cleaning equipment by the ultrasonic technique with commercial paste of abrasive hard particles used in mould polishing. Three factors were investigated: abrasive particle size, ultrasonic frequency and polishing time. The investigated alumina particle sizes were 0.05, 0.3, and 1.0 micron and the diamond particle size was 1.5 micron, which are the common sizes available in commercial paste for polishing metallography samples. The studied frequencies of the ultrasonic polishing process were 28 and 40 kHz, and the times of polishing process were 15, 30, and 45 minutes. Analysis of variance (ANOVA) of factor effects and two types of DOE analysis were employed to obtain the roughness Ra outcomes by empirical response surface modelling: 3x3 partial factorial design and 4x2 factorial design were used to investigate the surface roughness. The response surface modelling results indicate that the minimum surface roughness Ra of 0.21 micron obtained by ultrasonic polishing correspond to the frequency of 40 kHz, 20 minutes of polishing and alumina particle size of 0.7 microns.

Theoretical analysis of interfacial design and thermal conductivity in graphite flakes/Al composites with various interfacial coatings

Abstract Graphite flakes/Al composites are promising thermal management materials due to high thermal conductivity (TC) in basal plane orientation, matched coefficient of thermal expansion, and good machinability. In this article, the acoustic mismatch model and the effective medium approach are applied to predict the influence of different interfacial coatings on the interfacial thermal conductance (ITC) and the TC of graphite flakes/Al composites, respectively. With the increase in the thickness of interfacial coatings, the ITC and the TC of graphite flakes/Al composites decrease. For the composites with Ni, Cr/Cr7C3/Cr3C2, Si/SiC, Ti/TiC, WC, and Mo/Mo2C coatings, the ITC is sensitive to coating thickness. In order to obtain ideal TC of graphite flakes/Al composites, the thickness of the coatings should be controlled below 1 μm. It is reasonable that the TC of the graphite flakes/Al composites increases as the volume fraction of graphite flakes increases. The TC of the graphite flakes/Al composites increases with the ITC and changes slowly when the ITC increases to a certain extent. Si/SiC and WC coatings are proposed to be the most promising candidates to improve the thermal performance of graphite flakes/Al composites.

The enhancement of polymer composite coating by using a waste glass powder as alternative reinforcement

Epoxy-based composites are widely used as a surface coating in the aircraft, automobile and microelectronic industries due to theirs great mechanical properties, excellent strength-to-weight ratio, lightweight, and good machinability. However, the epoxy-based coating has poor corrosion resistance in a severe environment such as in seawater. The incorporation of various fillers into epoxy resins can yield high-performance composites having high strength, lightweight, multifunctional properties and also improve corrosion resistance. Therefore, this study focuses on the preparation of inorganic nanoparticles filled in an epoxy resin matrix to create high-performance composites. The waste glass powder (WGP) was selected to use as the alternative reinforcement in epoxy resin-based composites in order to search for a sustainable and recycling filler along with the use of commercial SiO2 as a comparative filler. The broken glass from household waste was processed through a high-speed vibratory milling technique until reaching the micrometer level. The physical properties, microstructure, mechanical properties, electrical properties, water absorption and corrosion resistance of all composites are investigated. The results show that after mixing WGP with an epoxy resin matrix, both Vickers hardness and abrasion resistance significantly increase compared to the neat epoxy resin whereas the water absorption ability of composites decreases. For the electrical properties, WGP does not show a significant effect on dielectric constant, dielectric loss and resistivity whereas the anticorrosive performances of the WGP/epoxy resin composite coating are improved.

SHS of highly dispersed powder compositions of nitrides with silicon carbide Review

The application of the process of self-propagating high-temperature synthesis (SHS) to prepare highly dispersed powder nitride-carbide compositions from the most common refractory nitride (Si3N4, AlN, TiN) and carbide (SiC) compounds with a particle size of less than 1 μm is considered. The advantages of composite ceramics over single-phase ceramic materials and such trends of its development as the transition to nanostructured ceramics and the application of in situ processes of direct chemical synthesis of nanoparticles of components in the composite body are described. The attractiveness of the SHS process as one of the promising in situ processes characterized by simplicity and cost-effectiveness, the possibility of obtaining highly dispersed ceramic powders by burning mixtures of inexpensive reagents is shown. Considerable attention is paid to the consideration of the results of the application of azide SHS, based on the use of sodium azide and gasified halide salts as part of mixtures of initial powders of nitrided and carbidized elements during their combustion in nitrogen gas. The review of publications devoted to the application of SHS to obtain highly dispersed composite powders Si3N4–SiC, AlN–SiC and TiN–SiC, promising for use in sintering of the corresponding composite ceramic materials of submicron and nano-sized structure with improved properties, lower brittleness, good machinability, lower sintering temperatures compared with single-phase ceramic materials made of nitrides or carbides as well as for other applications, is presented. The results of the application of azide SHS are presented in detail both in the form of the results of thermodynamic calculations and the results of experimental research of combustion parameters, combustion product structure and composition. The advantages and disadvantages of using the combustion process for the synthesis of nitride compositions with silicon carbide, the causes of the disadvantages and the directions of further research to eliminate them are discussed.

Optimal Design of the Flexure Mount for Optical Mirror Using Topology Optimization Considering Thermal Stress Constraint

An optical mirror assembly is an opto-mechanically coupled system as the optical and mechanical behaviors interact. In the assembly, a flexure mount attached to an optical mirror should be flexible in the radial direction, but rigid for the remaining degrees of freedom for supporting the mirror rigidly and suppressing the wavefront error of the optical mirror. This work presents an optimal design of the flexure mount using topology optimization with thermal stress constraint. By simplifying the optical mirror assembly into finite shell elements, topology optimization model was built for efficient design and good machinability. The stress at the boundary between the optical mirror and the mount together with the first natural frequency were applied as constraints for the optimization problem, while the objective function was set to minimize the strain energy. As a result, we obtained the optimal design of the flexure mount yielding the improved wavefront error, proper rigidity, and machinability.

Ultrastrong, Thermally Stable, and Food-SafeSeaweed-Based Structural Material for Tableware.

Widely used disposable plastic tableware is usually buried or directly discharged into the natural environment after using, which poses potential threats to the natural environment and human health. To solve this problem, nondegradable plastic tableware needs to be replaced by tableware composed of biodegradable structural materials with both food safety and the excellent mechanical and thermal properties. Here, a food-safe sargassum cellulose nanofiber (SCNF) is extracted from common seaweed in an efficient and low energy consuming way under mild reaction conditions. Then, by assembling the SCNF into a dense bulk material, a strong sargassum cellulose nanofiber structural material (SCNSM) with high strength (283MPa) and high thermal stability (>160°C) can be prepared. The SCNSM also possesses good machinability, which can be processed into tableware with different shapes, e.g., knives and forks. The overall performance of the SCNSM-based tableware is better than commercial plastic, wood-based, and poly(lactic acid) tableware, which shows great application potential in the tableware field.