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Composite manufacturers and consumers are increasingly turning to natural-based composites for their biocompatibility, cost-effectiveness, and widespread availability. This study investigates the potential of using teak wood dust as an economical filler material, combined with natural fibers, within an epoxy matrix to create a composite. Specifically, it examines how varying concentrations of teak wood dust—3 wt%, 6 wt%, and 9 wt%—affect the mechanical properties such as tensile strength, flexural strength, impact resistance, inter-laminar shear strength (ILSS), and hardness of an abaca-pineapple-epoxy hybrid composite. The composites were fabricated using the hand layup method followed by hot pressing. Among the different configurations, the composite with 6 wt% teak wood dust (SD-6) demonstrated superior performance, with improvements in tensile, flexural, ILSS, and impact strengths ranging from 3% to 35% compared to other variants. Scanning Electron Microscope (SEM) analysis of the fractured surfaces indicated that the inclusion of 6 wt% teak wood dust enhanced fiber-matrix adhesion, leading to improved mechanical properties of the composite.

This study investigates the mechanical properties of single and double-layer woven sisal mat-reinforced PP composite panels. Sisal fibers were extracted using the manual decortication method, resulting in fibers with a density of 1.43 g/cm3 and a diameter ranging from 0.4 mm to 0.6 mm. To improve the bonding between the sisal fibers and the matrix, the fibers were hand-spun into yarn and woven into mats. The study focuses on the unique material combination and the use of sisal as a natural fiber reinforcement. The 18 mm thick panels were tested for water absorption following ASTM D570, compression strength, and tensile strength following ASTM D3039 using the UTES-100 High Precision universal strength tester machine. Composite panels with single layers of 10% and 15% woven fabric mat, loaded with 8 kg and 10 kg, exhibited compressive strengths of 11.6KN and 12.5KN, respectively. Panels reinforced with two layers of 20% and 30% sisal woven fabric mat, loaded with 8 kg and 10 kg, had compression strengths of 12.2KN and 12.5KN, respectively. Moreover, composite samples with 15% single layer and 30% double-layer sisal woven fabric mat demonstrated a equal compression strength of 12.5KN, falling within the range recommended by ISO13006:2012. The tensile strength of 16.99MPa, although slightly below the recommended ISO13006 value of 20MPa for commercial-grade panels, indicates promising results. The study’s findings suggest that higher fiber content and additional reinforcement layers lead to increased compression and tensile strength. Furthermore, the moisture absorption rate of the developed composite panels was significantly lower than the 0.5% water absorption rate authorized by the American National Standard Institute.

The microstructures and properties of powder metallurgy Ti-45Al-10Nb (at.%) alloys fabricated by vacuum hot pressing consolidation of milled powder have been investigated. Under the sintering conditions, the alloy exhibits much fine-grained microstructure, which consists of a double phase γ + α2 microstructure containing Ti2AlC precipitates. Tensile properties are measured at 900 °C–1000 °C under a strain rate of 1 × 10−4 s−1. This alloy displayed outstanding high-temperature tensile strength, with tensile strength (UTS) 410.2 MPa and elongation (ε) 12.5% at 900 °C, and UTS 189 MPa and ε 16.7% at 1000 °C, respectively. [ABSTRACT FROM AUTHOR]

The present study is aimed at investigating a new approach of direct recycling using the hot press forging process. In the study, the chip sizes of AA6061 that produced from high speed milling were used and the mechanical property of the recycled chip of AA 6061 was studied. Response surface methodology (RSM) was used as the appropriate approach for the experimental design and optimization of the response investigated. Central composite design (CCD) based on face centred cubic design was applied in designing the experiments to evaluate the effects of three main operating variables. Three main operating variables investigated i.e. chip size, pre-compaction, and holding time was used to determine the mechanical properties by measuring the ultimate tensile strength (UTS)as the response variable. The results of mechanical property of the recycled chips were compared with the original AA6061 aluminium billet. Result of mechanical properties shows holding time has the most influential effect followed by pre-compaction, and chip size has the least effect on UTS. Hot pressed AA6061 aluminium alloy at holding time 120 minutes, 4 times pre-compaction cycle, and large chip size shows the best UTS with reasonablePred R 2 of 0.8866 and 98% suggested solution for desirability. Therefore, it can be concluded that, hot press forging could be one of the alternative metal waste recycling processes instead of conventional method that has been carried out without melting phase which contributes to a sustainable manufacturing process technology in the future. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) was electrospun into ultrafine fibrous membranes from its solutions in a mixture of N,N-dimethylformamide and acetone (9:1, v/v). The electrospun membranes were subsequently treated by continuous hot-press at elevated temperatures up to 155°C. Changes of morphology, crystallinity, porosity, liquid absorption, and mechanical properties of the membranes after hot-press were investigated. Results of scanning electron microscopy showed that there were no significant changes in fibrous membrane morphology when the hot-press temperature varied from room temperature to 130°C, but larger pores were formed because of fibers melting and bonding under higher temperatures. Analyses of X-ray diffraction and differential scanning calorimeter exhibited that the crystalline form of PVDF could transfer from β-type to α-type during hot-press at temperatures higher than 65°C. Tensile tests suggested that the mechanical properties of the electrospun PVDF membranes were remarkably enhanced from 25 to 130°C, whereas the porosity and the liquid absorption decreased. The hot-press at 130°C was optimal for the electrospun PVDF membranes. The continuous hot-press post-treatment could be a feasible method to produce electrospun membranes, not limited to PVDF, with suitable mechanical properties as well as good porosity and liquid absorption for their applications in high-quality filtrations or battery separators. POLYM. ENG. SCI., 48:934-940, 2008. © 2008 Society of Plastics Engineers, INTRODUCTION The electrospinning is a straightforward way to produce ultrafine fibrous membranes from polymer solutions or melts under a high electric voltage [1-5]. Because of the tiny diameter in several [...]

Co-based diamond tools are widely appreciated for their exceptional mechanical properties and good holding ability for diamonds. However, the reliance on cobalt (Co) poses challenges due to its high cost and scarcity as a strategic resource. A potential alternative is the Fe–Co–Cu alloy, emerging as a promising substitute for Co matrix alloys. In this work, hot-press sintering was utilized to create pure matrix and diamond tools utilizing Fe–Co–Cu pre-alloyed powders of varying compositions as raw materials without the use of any sintering additives. The investigation explores the influence of different Fe: Cu ratios on the mechanical properties of diamond tools produced from Fe–Co–Cu alloys, focusing on the diamond holding force, microstructure, and phase structure evolution. Results indicate that at a Co content of 15 wt% and Fe: Cu ratios ranging from 7.5:1 to 1:7.5, the Fe–Co–Cu alloy's phase structure primarily comprises α-Fe and a Cu-rich phase. Co predominantly exists in α-Fe as a solid solution. As the Fe: Cu ratio decreases, the alloy's phase structure gradually transitions from α-Fe to a Cu-rich phase, accompanied by a progressive decline in both bending strength and hardness, while the densities gradually increase. The matrix's holding force on the diamond exhibits an increasing and then diminishing trend, peaking at the Fe: Cu ratio of 6:1. The Fe–Co–Cu alloy sintered by hot-pressing has a nearly equiaxed grain structure with no obvious texture.

Poly(vinylidene fluoride)‐co‐hexafluoropropylene (PVDF‐HFP) co‐polymer films are prepared via solution casting followed by hot‐press method. Two different types of solvents, viz., solvent mixture DMF and acetone and single solvent only DMF are used to prepare two sets of samples which are then hot‐pressed at various temperatures (110, 120, and 130 °C) to study the effect of hot‐press temperature on samples prepared from different types of solvents. X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra shows formation of electroactive β‐phase whose fraction remaining above 71% for all the synthesized samples. Differential scanning calorimetry (DSC) is performed to obtain the degree of crystallinity of the as‐prepared samples and the hot‐pressed samples seemed to have a single exothermic melting peak instead of two in case of the casted ones. Dielectric properties and AC conductivity of the samples are also studied. The highest dielectric constant among the synthesized samples is found to be ≈12 at 1 kHz at room temperature. The static hysteresis loops are traced for all the as‐synthesized films. Remnant polarization is found to increase with increase in the hot‐press temperature, the coercive field remaining almost similar for all of them. The PUND analysis is also carried out for the all as‐prepared samples. A comparison study is presented through this report, emphasizing the influence of hot‐press temperature on β‐phase fraction of PVDF‐HFP films prepared from two different types of solvents, intended for energy harvesting and storage applications. [ABSTRACT FROM AUTHOR]

Magnesium alloy/PC/ABS composites were prepared by hot-press molding technology. The bonding strength is the crucial factor to influence the comprehensive performance of this composite, and it was closely related to the different processing parameters such as temperature, pressure and time. After exploring their relationship, the optimal hot-press processing condition was obtained. The micro- and nano-structure of composites also received attention. Before hot-pressed, the magnesium alloy surface was treated by micro-arc oxidation in order to construct the nano-sized pores. With the aid of scanning electron microscope (SEM) and atomic force microscope (AFM), a refined mechanical interlocking structure was observed with the formation of coordinate bonds at the interface of an alloy-polymer hybrid. The binding energy of the chemical elements at the bonding interface of the composite was also tested by X-ray photoelectron spectroscopy (XPS) and the analysis concluded that coordination bonds were formed at the bonding interface. The maximum tensile shear strength of the composite reached 9.48 MPa. [ABSTRACT FROM AUTHOR]

Unidirectional fiber‐reinforced composite laminates have limited resistance to out‐of‐plane impact and are prone to structural integrity damage during service due to low‐velocity impact (LVI). In this study, the hot‐press fusion method was employed to repair the impact‐damaged unidirectional carbon fiber‐reinforced poly‐ether‐ether‐ketone (CF/PEEK) thermoplastic composites. No delamination or matrix cracking induced by impact was observed in the repaired specimens, as confirmed by ultrasonic scanning and digital microscope. In addition, the hot pressing treatment enables the fibers to be covered again by the resin matrix, which eliminates fiber pull‐out and fiber/matrix debonding. Afterward, typical responses of CF/PEEK composite laminates to re‐impact and post‐repair compression are presented in a comprehensive and detailed manner, and compared with the initial impact response and compression after impact (CAI) behavior. The effects of three impact energies and two stacking sequences are considered. The results indicate that quasi‐isotropic laminates are more susceptible to localized fracture damage upon re‐impact as the impact energy increases, due to initial fiber breakage, compared to orthotropic laminates. The hot‐press treatment enhances the compression residual strength of the specimen by 20%–30% compared to its state before repair. These studies offer technical insights into the application of the hot‐press fusion method to enhance the mechanical properties of composite laminates post impact damage. [ABSTRACT FROM AUTHOR]

Ecological manageability in manufacturing these days is a dire and exceptional issue and the principle concerns are identified with increasingly proficient utilization of energy and materials. Recycling can save a large amount greenhouse gas emissions, particularly in the case of aluminum. The parameter on the innovative technique on the direct recycling was investigated by employing design of experiments, via hot press forging process (DR-HPF). Thus, reutilizing of aluminum chips AA6061 with full factorial 3 2 design of experiment comprising a variety of working temperature and holding time were employed. Central composite design (CCD) was applied to outline the experiments towards evaluating the influences of the hot press forging parameters to the three responses; ultimate tensile strength (UTS), elongation to failure (ETF), and global warming potential (GWP). In conjunction with this, the environmental impacts associated with DR-HPF process are evaluated alongside the resultant conventional recycling (CR) by using re-melting route as indication. Experimental measurements, literature analysis and industrial data were merged to acquire the analysis of aluminum recycling life cycle. Clear conclusions were successfully drawn through the attained results on the outlook proposed by solid state direct recycling for the purpose of reducing the environmental effects by taking material and energy conservation as one of the most essential impacting factor. The global warming potential of a DR-HPF route gives a significant environmental impact where it is reduced up to 69.2% in comparison to the conventional (melting) routes.

We applied microwave hot-press sintering for the first time for the fabrication of Fe-based diamond saw bits at low fabrication temperature and pressure. Specifically, we investigated the effects of sintering temperature and pressure on the microstructure and mechanical properties of the sintered samples. The results indicate that the alloy samples achieve complete densification and hardness up to 35.25 HRC at 820 ∘ C and 15 MPa for a sintering time of 5 min. The microstructure evolution process shows that the microstructure refinement gradually increases with increasing temperature. Moreover, the sintering temperature is the main controlling factor that determines the relative density, hardness, and microstructure. This work provides a new sintering strategy for metal powders in the field of super-hard tools. [ABSTRACT FROM AUTHOR]

The present article focused on the residual strains and deformation of the laminates fabricated by rapid hot press process using prepreg. Strain gauges and laser tracker were utilized to measure the residual strains and deformation of the laminates. By studying the effects of curing time and de-molding temperature on residual strains and deformation of composite laminates, the efficient curing conditions were proposed and good processing quality was ensured. The results indicate that the laminates with low curing degree incline to generate high residual stresses during curing and cooling processes. The effects of cure duration and de-molding temperature on the deformation degree and type of laminates are significant. In order to ensure both curing efficiency and low deformation, the curing time of the resin and de-molding temperature should be designed cautiously. The experimental results suggest that the curing duration longer than 12 min is needed, and the de-molding temperature should be no less than 40°C lower than glass transition temperature of the cured matrix. [ABSTRACT FROM AUTHOR]

Al-Si coating prevents the oxidation or decarburization of hot-press forming (HPF) steel. However, the high reactivity of Al with moisture promotes H uptake, and the coating hinders the out-diffusion of absorbed H atoms inside the steel, leading to hydrogen embrittlement (HE). This study added Sb to adjust Fe and Al/Si diffusivity, and forming H-trapping voids within the coating. Simultanesouly, these voids provided routes for the emission of H atoms, thereby improving the resistance to crack propagation during bending. The optimal design of the Al-Si coating by adjusting the Sb content and void fraction would enable extensive applications of HPF steel. [Display omitted] • Sb addition to Al-Si coated steel causes voids on the coating layer. • Kirkendall voids on the Al-Si coating layer trap hydrogen penetrating. • Voids on the Al-Si coating layer act as a route hydrogen emitting. • Voids on the Al-Si coating impede hydrogen permeation and promote hydrogen emission. [ABSTRACT FROM AUTHOR]

Five different soybean protein sources were added to wheat flour to increase the protein content by 15–25%, and the resulting composite flours were optimally processed into hot‐press tortillas in a pilot plant. The rheological properties of composite flours were evaluated with the farinograph, alveograph, and other wheat quality tests. Tortilla‐making qualities of the control and soybean‐fortified flours were evaluated during dough handling, hot pressing, and baking. The resulting tortillas were tested in terms of yield, physical and chemical parameters, sensory properties, color, and objective and subjective texture. The soybean‐fortified tortillas had increased yields because of the higher dough water absorption and enhanced essential amino acid scores. Among the five different soybean proteins, the defatted soybean flour (SBM1) with the lowest fat absorption index and protein dispersibility index (PDI) and the soybean concentrate produced the best fortified tortillas. The protein meals with high PDI and relatively lower water absorption index (SBM3 and SBM4) produced sticky doughs, lower alveograph P/L values, and defective tortillas. All soybean proteins produced higher yields of tortillas with an enhanced protein quality and amount of dietary fiber. [ABSTRACT FROM AUTHOR]

The sintering behaviour of 17Ni/(10NiO-NiFe2O4) cermet not only is influenced by the characteristics and impurities of the raw materials but also is dependent on extra pressure during the fabrication process. Our work was concerned with the effect of sintering pressure on the relative density, mechanical properties and electrical conductivity of 17Ni/(10NiO-NiFe2O4) cermet. The nickel-ferrite based cermet was prepared by hot press sintering technology at 1100°C for 120 min, and sintered at pressures ranging from 12 to 24 MPa. The microstructure, phase compositions and mechanical properties were studied by scanning electron microscopy, X-ray diffraction and three-point bending strength tests respectively. It was found that the relative density and bending strength of NiFe2O4 based cermet have a great influence upon the sintering pressure, and that the highest bending strength of 125·89 MPa could be obtained under a sintering pressure of 16 MPa. Meanwhile, it was shown that thermal shock resistance decreased as the sintering pressure increased. [ABSTRACT FROM AUTHOR]

Refined wheat flours commercially produced by five different U.S. and Mexican wheat blends intended for tortilla production were tested for quality and then processed into tortillas through the hot‐press forming procedure. Tortilla‐making qualities of the flour samples were evaluated during dough handling, hot pressing, baking, and the first five days on the shelf at room temperature. The predominant variables that affected the flour tortilla performance were wet gluten content, alveograph W (220–303) and P/L (0.70–0.94) parameters, farinograph water absorption (57%) and stability (10.8–18.7 min), starch damage (5.43–6.71%), and size distribution curves (uniform particle distribution). Flours produced from a blend of Dark Northern Spring (80%) and Mexican Rayon (20%) wheat had the highest water absorption, and tortillas obtained from this blend showed the highest diameter and lowest thickness. The whitest and best textured tortillas were obtained from the flour milled from three hard types of Mexican wheat blend. A Mixolab profile was generated from the best tortilla flours, those produced by mills 3 and 4. The Mixolab profile showed that a good flour for hot‐press tortillas had a relatively lower absorption and short dough mix time compared with a bread flour and should have a significantly higher gluten compared with an all‐purpose flour. Compared with bread flour, the tortilla flour had higher retrogradation and viscosity values. The Mixolab profile proved to be a good preliminary test to evaluate flours for hot‐press tortillas. [ABSTRACT FROM AUTHOR]

Hydrothermally synthesized ZnS nanopowders comprising small and large particles were used to synthesize ZnS ceramics. Small particles (200 nm) existed in the gaps between the large particles (0.7 μm) and assisted the densification of the ZnS ceramics. ZnS ceramics sintered at low temperatures (<1000°C) exhibited small grains with large grain‐boundary areas that provided diffusion paths for carbon ions from the graphite mold, resulting in carbonate absorption bands. ZnS ceramics sintered at high temperatures (≥1000°C) for a long time (≥2.0 hours) exhibited a dense microstructure with very large grains (>500 μm). The ZnS liquid phase, which was formed at approximately 980°C, assisted the densification and grain growth of the ZnS ceramics. A 3.0‐mm‐thick ZnS ceramic sintered at 1000°C for 16 hours showed a high Knoop hardness (321 kgf/mm2) and a high transmittance of 71% in the wavelength range 6.0‐12 μm without carbonate absorption bands. [ABSTRACT FROM AUTHOR]

A hot-press tackifying process was used to improve the mechanical properties of cured laminates in vacuum-assisted resin transfer molding by placing a thermoplastic film into the preforms at various pressures and temperatures. Three modified preforms were prepared at 0.1, 0.3, and 0.6 MPa using an autoclave, and the laminates were then produced via vacuum-assisted resin transfer molding. The mechanical properties of the modified laminates were tested and compared to those of the unmodified ones. The fiber volume fractions of the modified laminates decreased with increasing pressure. The tensile strength of the modified laminates at the three pressures improved by 16.78%, 41.21%, and 29.47%, respectively, compared to the unmodified samples. Modified laminates at 0.3 MPa showed better results than those at 0.1 and 0.6 MPa, which were all better than the unmodified samples. The modulus of the modified laminates from vacuum-assisted resin transfer molding was improved by 2.48%, 19.01%, and 13.22%, respectively. The effect of the hot-press tackifying in improving the tensile strength and modulus of a laminate on a pre-impregnated laminate (prepreg) using the autoclave was studied and compared to that of the unmodified case. Here, the tensile strength increased by 32.5% and 12.3%, respectively. [ABSTRACT FROM AUTHOR]

Owing to the ultrahigh refractive index, La2O3‐TiO2 glass is regarded as a promising candidate material in the field of lens, gemstones, and many other optics. However, due to its extremely low glass‐forming ability, it can only be obtained by rapid solidification processes such as melt quench or containerless solidification methods, leading to the limited size of as‐solidified products (for example, 1‐10 mm for containerless solidified sample), that are severely deferring the application of this novel high refractive glass. In this work, we aimed at preparing the larger sized bulk glasses over 10 mm, La2O3‐TiO2 glasses were successfully prepared by hot‐press sintering within the glass kinetic window. A small amount addition of SiO2 was found to effectively increase the glass‐forming ability while keeping high refractive index. When the content of SiO2 was 15 mol%, its transmittance could reach 54% at 800 nm and 72% in the infrared region (1 mm thick). Meanwhile, its refractive index could keep ultrahigh value above 2.14. And the sintering mechanism was studied according to the sintering shrinkage curve. It indicates that the plastic flow was the main mass transfer way in the densification process. [ABSTRACT FROM AUTHOR]

An austenitic Hadfield steel sheet shows a relatively low yield strength of 0.4–0.5 GPa and serrated flows in spite of excellent tensile strength and ductility along with highly-sustained strain hardening. In order to overcome the shortcomings, a multi-layer steel (MLS) sheet was fabricated by a roll-bonding with an ultra-high-strength martensitic hot-press-forming (HPF) steel sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2% of C) to HPF (0.23% of C) layers, and could generate a kind of very thin multi-layers of 35 μm in thickness. All tensile properties of the Hadfield/HPF MLS sheet (yield strength; 946 MPa, tensile strength; 1291 MPa, elongation; 44.5%) were superior to those of the Hadfield sheet. Interestingly, the persistent elongation up to 44.5%, which is higher than that of the Hadfield steel, in the present MLS sheet is a quite unique and interesting characteristic. The simultaneous enhancement of strength and ductility of the MLS sheet was explained by the contributions of 1) populated twin formation, 2) generation of geometrically necessary dislocations (GNDs), and 3) increase of back stress inside thin interfacial layers. [ABSTRACT FROM AUTHOR]

The drying kinetics of poplar lumber was experimentally investigated as a function of drying temperature (115, 135, 160, 185 and 205°C) during a periodic hot-press-drying process. Poplar lumber was dried under contact (compression ratio of 10%) and high-press states (compression ratio of 44%). Compared with the contact-state, the high-press-state showed higher drying rate and higher efficiency of removing free water than bound water in wood. Eight mathematical models from the literature were established to analyze the drying behavior. The Weibull model, with an average determination coefficient R2 of 0.9958, fitted well for all applied drying conditions. The scale parameter decreased with increasing drying temperature and was lower for high-press-state drying compared with that for contact-state drying. Moisture diffusivity and activation energy were calculated according to the Weibull model. Diffusivity increased with increasing drying temperature, with the average value of 1.734 × 10-6 and 3.313 × 10-6 m2/s and activation energy of 34.79 and 32.85 kJ/mol for contact-state drying and high-press-state drying, respectively. Hot-press drying created an M-shaped curve of density distribution, with high density at the two surface regions gradually decreasing toward the core region. The contact state-dried wood showed increased density near the wood surface. Both average density and peak density improved in the case of high-press-state-dried wood. Furthermore, the hydrophilic index of wood for high-press-state drying was lower than that of the contact-state drying, and the opposite was true regarding crystallinity index. The hygroscopicity of high-press-dried poplar decreased with lower equilibrium moisture content and higher moisture excluding efficiency, compared with contact-state-dried poplar. The rapid, high-quality drying of poplar lumber through periodic hot-press was more potentially achieved by the high-press-state compared with contact-state drying. [ABSTRACT FROM AUTHOR]

In this study, two different compositions of submicron-structured titanium (760 nm) and micron-structured chromium (4.66 μm) powders were mixed to fabricate Cr-31.2 mass% Ti alloys by vacuum hot-press sintering. The research imposed various hot-press sintering pressures (20, 35 and 50 MPa), while the sintering temperature maintained at 1250°C for 1 h. The experimental results showed that the optimum parameters of the hot-press sintered Cr-31.2 mass% Ti alloys were 1250°C at 50 MPa for 1 h. Also, the relative density reached 99.94%, the closed porosity decreased to 0.04% and the hardness and transverse rupture strength (TRS) values increased to 81.90 HRA and 448.53 MPa, respectively. Moreover, the electrical conductivity is enhanced to 1.58 × 104 S·cm-1. However, the grain growth generated during the high-temperature and high-pressure of the hot-press sintering process resulted in the grain coarsening phenomenon of the Cr-31.2 mass% Ti alloys after 1250°C hot-press sintering at 50 MPa for 1 h. In addition, the Cr-31.2 mass% Ti alloys were fabricated with the submicron-structured titanium (760 nm) and chromium (588 nm) powders showed more effective compaction than the micron-structured titanium (760 nm) and chromium (4.66 μm) powders did. The closed porosity decreases to 0.02% and the hardness values increase to 83.23 HRA. However, the agglomeration phenomenon of the Cr phase and brittleness of the TiCr2 Laves phases easily led to a slight decrease in TRS (400.54 MPa). [ABSTRACT FROM AUTHOR]

In the present research, two different compositions of submicron-structured cobalt (800 ± 45 nm) and chromium (700 ± 50 nm) powders are mixed to fabricate Co-50 mass% Cr alloys by the vacuum hot-press sintering technique. This study imposes various hot-press sintering temperatures (1150, 1200, 1250 and 1300°C) and pressures (20, 30, 40 and 50 MPa) while maintaining the sintering time at 1 h, respectively. The experimental results show that the optimum parameters of hot-press sintered Co-50 mass% Cr alloys are 1200°C at 50 MPa for 1 h. Meanwhile, the sintered density reaches 7.73 g cm−3, the closed porosity decreases to 0.31%, and the hardness and transverse rupture strength values increase to 80.6 ± 0.3 HRA and 1052.9 ± 17.5 MPa, respectively. Grain growth is not obviously generated after 1200°C hot-press sintering at 50 MPa for 1 h. Consequently, the optimal solid-phase sintering process effectively improved hot-press sintered Co-50 mass% Cr alloys, which resulted in the good properties. [ABSTRACT FROM AUTHOR]

High strength steel has attracted a lot of attention due to its excellent advantage of weight reduction. A thin Al-Si coating covered on the surface of hot-press-forming (HPF) steel offers functions of antioxidation and decarburization under high temperature processing conditions. In this study, the microstructure characteristic, phase, microhardness, and tensile strength of laser welded Al-Si coated HPF steel joints were investigated at different laser powers. Experimental results show that the welding process becomes unstable because of metallic vapor generated by ablation of the coating. Some of the white bright rippled Fe-Al phase was observed to be distributed in the fusion zone randomly. It is found that microhardness, tensile strength, and cupping test qualification rate decreases with the increase of the laser power. For the 1.1 kW laser power, the sound weld performs the best mechanical properties: Microhardness of 466.53 HV and tensile strength of 1349.9 MPa.

[Display omitted] • Quaternary Ag 2 SbBiSe 4 NCs are synthesized by a colloidal synthesis route. • Ag 2 SbBiSe 4 has a cubic crystal structure and a wide band gap. • Ag 2 SbBiSe 4 maintains low lattice thermal conductivity of ca. 0.34 W m−1K−1. • Modulation doping through Sn NCs is used to tune the TE performance of Ag 2 SbBiSe 4. • A maximum ZT value of 0.64 at 760 K and a high Vickers Hardness of ~185 Hv are obtained. Materials with low intrinsic thermal conductivity are essential for the development of high-performance thermoelectric devices. At the same time, the solution processing of these materials may enable the cost-effective production of the devices. Herein, we detail a high-yield and scalable colloidal synthesis route to produce Ag 2 SbBiSe 4 nanocrystals (NCs) using amine-thiol-Se chemistry. The quaternary chalcogenide material is consolidated by a rapid hot-press maintaining the cubic crystalline structure. Transport measurements confirm that n -type Ag 2 SbBiSe 4 exhibits an inherently ultralow lattice thermal conductivity of ca. 0.34 W m−1K−1 at 760 K. Moreover, a modulation doping strategy based on the blending of semiconductor Ag 2 SbBiSe 4 and metallic Sn NCs is demonstrated to control the charge carrier concentration in the final composite material. The introduction of Sn nanodomains additionally blocks phonon propagation thus contributing to reducing the thermal conductivity of the final material. Ultimately, a peak thermoelectric figure of merit value of 0.64 at 760 K is achieved for n -type Ag 2 SbBiSe 4 -Sn nanocomposites that also demonstrate a notable Vickers hardness of 185 HV. [ABSTRACT FROM AUTHOR]

The widespread use of synthetic composite materials has raised environmental concerns due to their non-biodegradability and energy-intensive production. This paper explores the potential of natural composites, specifically flax–polypropylene, as a sustainable alternative to traditional composites for semi-structural applications. In fact, the mechanical properties of flax–polypropylene composites are similar to synthetic ones (such as those made with E-glass fibers). However, processing challenges related to fiber–matrix interaction and material degradation necessitate suited process parameters for this sustainable type of material. For this reason, this review highlights the importance of optimizing existing manufacturing processes, such as hot press molding, to better accommodate the specific characteristics of polypropylene–flax composites. By refining the parameters and techniques involved in hot press molding, researchers should overcome current limitations and fully capitalize on its potential to produce composite materials of optimal quality. Therefore, a comprehensive literature assessment was conducted to analyze the properties and processing challenges of flax–polypropylene composites. Key process parameters affecting the material's performance are identified and discussed. By optimizing process parameters for flax–polypropylene composites, it is possible to develop a sustainable and high-performance material with a reduced environmental footprint. Further research is needed to scale up production and explore different applications for this sustainable composite material. [ABSTRACT FROM AUTHOR]

Graphite/Al composites have received widespread attention due to high thermal conductivity, low density, and excellent processability. In this study, a new process for preparing graphite/Al composites is proposed, which includes preparing Sn-Ag-Ti modified graphite films and then hot pressing and sintering them with aluminum to form laminated composites. The influence of different process parameters on the microstructure and thermal conductivity of a novel modified graphite film/Al composites was investigated. The results show that at 600 °C/30 min/5 MPa, the composites with 57.2 % graphite volume fraction has the highest heat flux of 2.536 J/s, which is higher than Cu 1.636 J/s, and the tensile strength is 45.72 MPa. The thermal conductivity of the large plate measured by the steady-state method is 677 W/(m·K), which is 92.8 % of the theoretical thermal conductivity. [Display omitted] • Sn-modified graphite film/Al laminated composite material has good interfacial bonding. • SnAgTi effectively fill the gap between graphite film and aluminum during sintering. • The heat flux of composite materials is 1.5 times that of Cu. • The thermal conductivity measured by steady-state method reached to 677 W/(m·K). [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have attracted considerable attention due to their unique phase structures and excellent properties. However, the existing preparation processes for HEAs involve high temperatures, lengthy procedures, and high costs, which limit their practical applications and confine them to the realm of fundamental research. Here, a novel method combining low-temperature solid-phase molten salt electrolysis and hot-press sintering was proposed to prepare CoCrFeNi HEA. Moreover, the study explored the addition of metal V, to modulate the composition of the HEA and improve its mechanical properties. The results showed that the molten salt electrolysis process could achieve the direct deoxidation of metal oxide mixtures, enabling one-step preparation of HEAs. During the early stages of deoxidation, the metals Ni and Co were obtained first and, under the influence of the mixed entropy, formed a non-stoichiometric NiCoCr alloy. As deoxidation progressed, Cr and Fe were successively reduced and further alloyed with the NiCoCr to form the non-stoichiometric CoCrFeNi HEA. Eventually, the aggregated dendritic metal Fe diffused and solid-solved into the non-stoichiometric CoCrFeNi HEA, resulting in the formation of a stoichiometric CoCrFeNi HEA. The CoCrFeNiVx (x = 0, 0.5, 1, 1.5) alloy maintained a single-phase FCC structure, where V effectively improved the hardness of the CoCrFeNi HEA, with minimal impact on its phase structure. V played a role in solid-solution strengthening, grain refinement, and reducing Cr segregation in the alloy. Additionally, the appropriate addition of V simultaneously increased the tensile strength, hardness, and ductility of the CoCrFeNi HEA.