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3D printing has witnessed a remarkable surge in popularity due to its flexibility in design and adaptability as a manufacturing technique to nearly each industrial area. This study focuses on harnessing the technological versatility of 3D printing by utilizing both standard poly lactic acid (PLA) and copper powder‐doped PLA to fabricate intricate structures through a layer‐by‐layer additive manufacturing process. The other innovation introduced here lies in the postprocessing step, which involves salt remelting. The mechanical properties of 3D‐printed standard test specimens undergo comprehensive assessment, encompassing bending and tensile evaluations, hardness measurements, density assessments, dimensional stability analyses, and wear resistance examinations. Utilizing copper powder‐doped PLA for the initial and final layers in XYZ‐oriented prints enables multimaterial printing, resulting in an ≈14% increase in tensile strength. Subsequently, subjecting this multimaterial composite to salt remelting elevates the strength enhancement to ≈16%, accompanied by a significant boost in rigidity by reducing voids in cross‐sectional area. In addition, scanning electron microscope images are captured, allowing for a detailed morphological analysis, which is then correlated with the findings of the various tests performed. This research unveils the potential of 3D printing technology in crafting materials with tailored mechanical properties, advancing its applicability in numerous industrial sectors. [ABSTRACT FROM AUTHOR]

Spark plasma sintering (SPS) is a new sintering method having shorter sintering time and higher densification speed than the traditional sintering methods. In this paper, the Si3N4/TiC ceramic tool material is sintered by SPS. The microstructure and mechanical properties of the material under different sintering parameters are compared. The sintering process of the material is then analyzed, and the best sintering parameters are obtained. Heat the material to 1600°C and keep the temperature for 15 min, then continue to heat to 1700°C and keep the temperature for 10 min, Si3N4/TiC ceramic tool material has high mechanical properties, its bending strength, fracture toughness, and Vickers hardness are 959 MPa, 8.61 MPa·m1/2, and 15.21 GPa, respectively. The scanning electron microscope (SEM) analysis shows that under this condition, the sintering additives and Si3N4/TiC material form the liquid phase, which makes the Si3N4 particles rearrange, dissolve, precipitate, and transform into rod shape β‐Si3N4. In addition, under the action of pulse current and external pressure, electric sparks are generated between TiC particles, which allows the material transfer and particle refinement. Therefore, the β‐Si3N4 has uniform grain size, and it is vertically and horizontally arranged in the structure, which makes the material have excellent mechanical properties. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the mechanical properties and ceramic bond of additively manufactured and milled dental zirconia materials. Materials and Methods: Disc (r = 10 mm, h = 2 mm) and bar (25×$\ \times \ $4 × 1. 2 mm) shaped milled (M group) (Nacera Pearl; Doceram) and additively manufactured (AM group) (NanoParticle Jetting; XJet, Carmel 1400) zirconia specimens were prepared for 2 experimental groups. Ceramic was applied to the disc specimens (h = 4 mm, r = 6 mm) (n = 9) and their shear bond strength (SBS) was measured. The surface morphology of disc specimens was analyzed with a scanning electron microscope (SEM). The Vickers microhardness (Vh), surface roughness (Ra), and three‐point flexural strength (FS) of bar specimens (n = 9) were measured. Results were statistically analyzed with Mann‐Whitney U‐test (α = 0.05). Results: Significant differences were found in FS and Vh values of the M and AM groups. M group (1501.4 ± 60.1 HV1) showed a significantly higher Vh value than the AM group (1169.2 ± 48.4 HV1) (p < 0.001). FS of the M group (1287.5 ± 115.2 MPa) exhibited significantly high value than the AM (1030.0 ± 29.2 Mpa) group (p < 0.001). Statistically, no significant differences were seen in SBS and Ra values of the M and AM groups. Conclusion: Within the limitations of this in vitro study, the manufacturing technique affected the mechanical properties of the zirconia materials. AM zirconia material showed lower Vh and FS values than M zirconia. Additionally AM zirconia demonstrated adequate bond strength with dental ceramic. [ABSTRACT FROM AUTHOR]

ZnS‐reinforced ZnS/ZnSe composites are prepared by chemical vapor deposition. Scanning electron microscope, transmittance, and bending strength are used to characterize the samples. The schematic diagram of the transmittance model of the double‐layer composite window is used to calculate the theoretical transmittance, and the measured value of the transmittance of ZnS/ZnSe composite material is in good agreement with the calculated value. The effects of interface layer on the optical and mechanical properties of materials are studied in detail. It is found that the interface can affect the transmittance of the composites, but it still maintains a high transmittance, and the influence of interface layer on the transmittance of visible band is more serious than that of infrared band. Moreover, the mechanical properties of the new composite material are significantly improved (35%). [ABSTRACT FROM AUTHOR]

This paper aims at improving the mechanical properties of coir fiber reinforced polyester composites through impregnation of rice husk and boiled egg shell in polyester matrix. The composites sheets were manufactured by varying the fabrication parameters such as fiber length, particulate content and fiber content. The mechanical properties of the fabricated composites were determined as per ASTM standards and the effects of fiber length, particulate content and fiber content on mechanical properties of rice husk and boiled egg shells impregnated coir - polyester composites were studied. Scanning electron microscope analysis was used to characterize the fracture behavior of the composites. The investigation witnessed the improvement in mechanical properties on addition of rice husk particulate in coir fiber reinforced polyester composites. Similarly the addition of boiled egg shell in to the composites has enhanced mouldability of the composites. The SEM investigation evidenced the arrest of crack propagation and voids formation on addition of rice husk and egg shell particulates in polyester matrix. This study confirmed the possibility of using rice husk and boiled egg shell impregnated coir fiber reinforced polyester composites in low load bearing applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The fatigue life of ZEK100 magnesium alloy in the phosphate buffered solution for various immersion intervals was investigated by experiments and theoretical predictions. The biodegradable behaviours of ZEK100 magnesium alloy were also studied. Microstructure observation showed that the corrosion behaviours were characterized by pitting corrosion. The corrosion rate decreased a lot in the initial 7 d and then almost stayed unchanged. After 28 d immersion, the elastic modulus almost kept stable, while the yield strength and the ultimate strength decreased a lot, which indicated that corrosion had important effects on the tensile mechanical properties. It showed that the fatigue life of the samples under the same stress conditions decreased with increasing immersion time under the asymmetric stress-controlled cyclic loading. Considering the effect of corrosion on the material failure, a modified fatigue life model was proposed for magnesium alloy under corrosion. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the influence of nanoparticle loading level on properties of experimental hybrid resin luting agents. Materials and Methods: Silanated 2-μm barium borosilicate glass microparticles and 7-nm silica nanoparticles were used. Five materials were obtained by loading a photocurable Bis-GMA/TEGDMA co-monomer with a total mass fraction of 60% inorganic fillers. The mass fraction of nanoparticles was set at 0% (control), 1% (G1), 2.5% (G2.5), 5% (G5), or 10% (G10). The properties evaluated were flexural strength (σ) and modulus (Ef), Knoop hardness number (KHN), and film thickness (FT). Dispersion/interaction of the particles with the resin phase was assessed by scanning electron microscopy (SEM). Data were submitted to statistical analysis (5%). Results: For σ, G1 > G2.5 = G5 = G10, and control > G10. For Ef, G2.5 > control = G1 > G5 > G10. For KHN, G5 = G10 > control = G1 = G2.5. For FT, G10 = G5 > control = G1, and G10 > G2.5. Incorporation of nanoparticles was associated with observation of clusters in the SEM analysis. The clusters were more frequent for higher nanoparticle loadings. Conclusion: Modest incorporation of nanoparticles may improve the properties of resin luting materials. Nanofiller mass fractions above 2.5% should, however, be avoided because they may be detrimental to the properties of the resin luting agents. [ABSTRACT FROM AUTHOR]

Ultrasonic motors (USMs) are driven by friction forces between a stator and rotor. So the output properties and life of USMs are strongly related to the properties, such as the mechanical and tribological properties, of the frictional materials. In this study, the effects of the content of potassium titanate whiskers (PTWs) on the mechanical and tribological properties of polytetrafluoroethylene (PTFE)-based friction materials and the performances of the corresponding USMs were studied. The morphology of worn surfaces of PTFE composites were observed with a scanning electron microscope. The experimental results show that the PTWs not only increased the hardness and elastic modulus of the PTFE composites but also increased the friction coefficient and wear resistance of the PTFE composites. On the whole, the PTFE-based friction materials filled with 5 wt % PTWs were the preferable friction materials for USMs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Overused vegetable oils, which are considered to be a waste and available in huge quantities after frying processes, were directly ethoxylated using a conventional cheap catalyst in order to obtain an economically valuable ethoxylated product to replace the imported intermediate derivatives and at the same time the environment will be rid of one of its pollutants. Therefore, this work was devoted to exploring its application as a fatliquoring agent in the leather industry. Overused sunflower and olein oils were directly ethoxylated using ethylene oxide gas in the presence of 3% KOH catalyst at 180 °C for 20 h. The prepared products were applied as nonionic fatliquors. The fatliquoring process is the operation in which a fatty matter is introduced into the leather fibers. The results obtained showed that the prepared ethoxylated overused oils were effective fatliquors with high HLB values giving stable oil in water emulsion as well as high stability against acid, alkali and different metallic salts. The fatliquored leather had improved mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement of the texture of the treated leather by the two prepared fatliquors as indicated from the scanning electron microscope images was observed. Also the results indicated that ethoxylated overused sunflower oil gave better results than those of ethoxylated overused olein oil. [ABSTRACT FROM AUTHOR]

To improve fire retardant behavior of bio‐epoxy resin, composites were prepared with three fire retardants (FRs); ammonium polyphosphate, aluminum trihydrate, and magnesium hydroxide. Fractured surfaces of prepared composites were observed with the scanning electron microscope (SEM). Tensile strength and Charpy toughness were evaluated and analyzed statistically using analysis of variance (ANOVA). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to determine the thermal stability. SEM analysis results revealed fractured surfaces were altered with addition of FRs. Adding FRs can be regarded as a decrease in tensile strength and toughness complemented by improved stiffness. ANOVA analysis showed FR/bio‐resin composites have a statistically significant loss in tensile strength, stiffness, elongation, and Charpy toughness. The DSC results showed the glass transition temperature was not affected significantly by adding FRs and ranged from 66 to 69 °C. TGA showed the initial, midway, and maximum decomposition temperatures for composites and their ability to form improved ash yields compared to pure resin. Aluminum trihydrate and Mg(OH)2 had higher T50 suggesting an increase in thermal stability compared to pure bio‐epoxy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47398. [ABSTRACT FROM AUTHOR]