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Currently, the strength of hot-press-forming steel has been increased to produce lightweight vehicles, and in this study, the first arc welding investigation on a 2.0 GPa-strength hot-press-forming steel was conducted. Hot-press-forming steel sheets with thicknesses of 1.1 mm were butt-welded by gas tungsten arc welding without a filler metal, with the heat input controlled in the range of 140-260 J/mm. The weld metal, coarse-grained heat-affected zone (HAZ), and fine-grained HAZ had martensitic microstructures. The softened zone was composed of an intercritical HAZ (with polygonal ferrite and martensite/bainite) and a subcritical HAZ (with tempered martensite). The intercritical HAZ was softened the most during welding and fractured during tensile testing. The strengths of the arc welds were in the range of 1141-1264 MPa, which were 57-63% strength of the base metal. The equiaxed austenite on martensite or ferrite matrix was developed at the intercritical HAZ of gas tungsten arc welds, therefore transforming into the coarse martensite during quenching. However, the intercritical HAZ of laser welds indicated acicular austenite transforming into the fine martensite due to its high cooling rate. The intercritical HAZ softening was revealed to originate from carbon diffusion during the martensite to austenite transformation, which is unavoidable in arc welding and should be considered in the design of a welded structure. [ABSTRACT FROM AUTHOR]

Hot press forming of Zn coated 22MnB5 is an effective way of producing ultrahigh strength structural parts for automobiles. The austenization process in hot press forming was investigated in our work. The results showed that the interfacial Fe 2 Al 5 inhibition layer in coated steel plays a critical role in diffusion during the austenization process. We proposed three stages of diffusion based on the level of stability of the inhibition layer (i.e. , the non-diffusion, inhomogeneous diffusion and homogeneous diffusion stages). The progression of diffusion in the coating through the three diffusion stages was discussed using Fe–Zn binary phase diagram and the Zn liquid +α-Fe(Zn) region was considered as the susceptible area to cracking. The penetration of liquid Zn into the substrate through grain boundary (GB) diffusion was observed after the breakdown of the interfacial Fe 2 Al 5 inhibition layer. In addition, we identified a transition diffusion layer at the interface which we assumed to be a result of the relatively long-term bulk diffusion of liquid Zn. The transition diffusion layer was analyzed following hot tensile tests. The structure of the layer was identified as body-centered cubic (BCC) α-Fe with large amounts of dissolved Zn. Although GB diffusion of liquid Zn into substrate was not observed because of the presence of the transition diffusion layer at the interface, the liquid metal induced embrittlement (LMIE) was not avoided for the Zn coated 22MnB5 in the hot tensile test. The results suggest that the BCC α-Fe phase is also sensitive to liquid Zn. • Interdiffusion between coating and substrate is controlled by the Fe 2 Al 5 inhibition layer. • Three diffusion modes (non-diffusion, inhomogeneous diffusion and homogeneous diffusion) are proposed. • The initial penetration of liquid Zinc through GB is observable. • Crack behavior is investigated using hot tensile test to determine mechanism of liquid Zinc induced embrittlement. [ABSTRACT FROM AUTHOR]

Abstract We investigated he thermoelectric (TE) properties and microstructures of Na-doped PbTe compounds, synthesized by various milling and sintering processes. It has been generally accepted that spark plasma sintering (SPS) inhibits grain growth due to the short sintering time, which is beneficial to the nano bulk composite. In contrast, we observed abnormal grain growth for SPS, unlike hot press (HP) sintering. Considering the Gibbs free energy change during sintering, the HP sintering increases internal energy while the SPS increases entropy energy, which causes the abnormal grain growth. Lattice strain and Fourier transform analyses of the transmission electron microscope images showed that the SPS sintered samples had more significant lattice strains and defects than the HP sintered samples. The low thermal conductivity of the SPS sintered samples was not from grain boundary phonon scattering but from phonon scattering by lattice strains and defects. The lattice strains and defects decreased electrical conductivity as well, resulting in deterioration of the power factor and thermoelectric performance. This suggests that the lattice strains and defects are more critical factors for enhancing thermoelectric performance than particle and grain size control. Highlights • Abnormal grain growth driven by entropy energy change is significant in spark plasma sintering. • SPS sintered samples have more significant lattice strains and defects than those of hot press. • Phonon scattering by lattice strains and defects decreases lattice thermal conductivity in SPS. • The lattice strains and defects decreases electrical conductivity as well. [ABSTRACT FROM AUTHOR]

Boron nitride-barium aluminosilicate (BN-BAS) composite ceramics were fabricated by the sol-gel method and hot-pressed sintering. The effects of the introduction method of BAS and sintering temperature on the phase assemblage, density, apparent porosity, mechanical properties and microstructures of the h-BN composite ceramics were investigated. The following two introduction methods were adopted: (A) BAS gel powder was prepared by the sol-gel method and then mixed with h-BN for hot pressing sintering, and (B) the BN-BAS composite powder was first prepared by the sol-gel method and then hot-pressed and sintered. The results indicate that the density, bending strength and fracture toughness of the latter are higher than those of the former when other conditions are the same. In the gel step of Group B, BAS has been coated on the surface of BN particles in dots, chemical bonding has existed, the distribution of BAS is more uniform, and it can better serve as a sintering aid. The BN-BAS composites prepared by both methods achieved the maximum mechanical properties at a sintering temperature of 1700 °C, and the density, apparent porosity, bending strength and fracture toughness of Group A were 2.40 g/cm3, 1.82%, 132.8 MPa and 2.3 MPa m1/2, while those of Group B were 2.42 g/cm3, 1.45%, 162.9 MPa and 2.7 MP m1/2. [ABSTRACT FROM AUTHOR]

In this study, the effects of rhenium on the evolution of microstructure and texture in hot press sintered tungsten heavy alloy (93W-4.9Ni-2.1Cu) is examined. Rhenium is added (i.e., increased rhenium from 0 to 1 wt % with interval of 0.25 wt %) to a conventional tungsten heavy alloy while maintaining a constant Ni: Cu (7:3) ratio. The samples were prepared using a vacuum hot press sintering method with parameters including 50 MPa pressure, 10 °C/min heating rate, and 1450 °C temperature for a 20-min holding time. The impact of rhenium on densification, crystallographic texture development, and grain boundary features of Re alloyed WHA was studied using electron backscattered diffraction (EBSD). The development of grain boundary texture was the result of a Ʃ3 CSL increase in sintered compact. The base alloy exhibits fibre texture in the (001) plane with the <111> direction and a higher proportion of low-angle grain boundaries. Reduced kinetics of grain growth during sintering led to a higher degree of densification and randomised weak fibre texture in rhenium-alloyed samples. The deterioration of texture in the (001) <111> direction in rhenium-added alloys was caused by recrystallization following recovery during sintering. Metallographic studies reveal that an increase in rhenium in the WHA's stoichiometry resulted in particle refinement during sintering, thereby enhancing the WHA's properties. Maximum micro-hardness (432 HV 0.5), electrical conductivity (23.74 % of IACS), and relative density (99.90 %) were observed in a 93W-4.9Ni-2.1Cu (Re 1 wt% alloy). • A close theoretical density of the 92W-4.9Ni-2.1Cu-1Re alloy was obtained. • An increase in the Ʃ3 CSL boundary impacts the grain boundary's texture. • Increasing rhenium stoichiometry in WHA resulted in a (111) 001> texture that is weaker. • Hardness and conductivity showed Re is an effective reinforcement for WHA. [ABSTRACT FROM AUTHOR]

Different stoichiometries of lead-free BaZr 0.2 Ti 0.8 O 3 –Ba 0.7 Ca 0.3 TiO 3 (BCZT) prepared by mechanosynthesis and sintered by either conventional sintering (CS) or hot pressing (HP) techniques were studied to establish the dependence of piezoelectric and dielectric properties on sintering parameters and microstructure. All synthesized stoichiometries showed a pseudocubic perovskite phase with homogeneously distributed A- and B-cations in the structure. The BCZT retained the pseudocubic symmetry after sintering and an average grain size <1.8 µm was obtained in all cases. HP sintering hindered the secondary phase segregation observed in the CS ceramics and increased the relative density. Piezoelectric coefficients (d 33) ranging from 5.1 to 21 pC/N and from 10.0 to 88.0 pC/N were obtained for CS and HP ceramics, respectively, despite the pseudocubic symmetry and the fine grain size. The higher d 33 values for the HP ceramics are a consequence of the higher density, better chemical homogeneity and lower sintering temperature and time required for the mechanosynthesized BCZT powders with high sintering activity. • BCZT were successfully formed by high-energy mechanosynthesis after 120 min. • Fine-grained BCZT were obtained by either conventional sintering or hot pressing. • HP sintering favored the presence of different crystal structures and higher density. • d 33 values ranged from 5.1 to 88.0 pC/N, depending on stoichiometry and sintering. [ABSTRACT FROM AUTHOR]

Herein, we develop a commercial-scale anion exchange membrane (AEM) water electrolyzer with exceptional durability that employs a Co oxide anode and commercial Pt/C cathode. The anode of the AEM water electrolyzer was developed using a simplified one-step hot-pressing process utilizing a single-phase Co oxide to achieve a uniform electrode surface and simplify the fabrication process. The Co oxide electrode obtained at the optimal hot-pressing temperature of 250 °C, exhibited excellent durability and catalytic activity compared to electrodes synthesized at other temperatures. This can be attributed to its spinel structure and the presence of Co3+ as the primary active site for the oxygen evolution reaction. The AEM water electrolyzer demonstrated remarkable performance, with a high hydrogen production efficiency of 79.46% and ultra-low degradation rate of only 2 mV kh−1 during a long-term durability test of 1000 h at 50 °C. These results indicate the exceptional potential of the AEM water electrolyzer comprising a Co oxide anode as a promising technology for efficient and sustainable production of high-purity hydrogen. We are developing a highly durable and uniform Co-based OER electrode for a commercial-scale anion exchange membrane water electrolyzer. The CO_250 electrode is fabricated by a one-step Hot-pressing process. It shows a hydrogen production efficiency of 79.46% and an ultra-low degradation rate of only 2 mV kh−1 for 1000 h at 50 °C in 0.1 M KOH, significantly lower than the recently reported durability results. [Display omitted] • Developed highly durable and uniform Co-based OER electrodes for AEMWE systems. • Employed a simplified one-step hot-pressing process. • The fabricated CO_250 electrode exhibits excellent OER activity and durability. [ABSTRACT FROM AUTHOR]

Boron carbide (B4C) is an essential material in various high-performance applications due to its light weight and hardness. In this work, B4C-based composites were fabricated via a powder route consisting of powder mixing, precursor preparation, and hot-pressing under vacuum. The composites' mechanical properties and microstructure were analyzed to investigate the effect of adding minor second-phase particles. In addition to homogenizing the grain size, the addition of SiC (≤10 wt%) to B4C increased its strength and improved its fracture toughness, with values reaching 551 MPa and 3.22 MPa m1/2, respectively. Meanwhile, the addition of TiB2 (≤10 wt%) significantly improved the strength and fracture toughness only, with values reaching 548 MPa and 3.92 MPa m1/2, respectively, with only a minimal decrease in hardness. Microstructural analysis revealed that the second-phase particles were uniformly distributed and reduced the average grain size, contributing to the increase in strength. Additionally, the TiB2 particles impeded crack propagation and induced crack deflection at the interface, indicating the formation of an intergranular fracture mode. On the contrary, the addition of SiC primarily resulted in transgranular fracture behavior, though it still improved the toughness of the B4C. These results suggest that small amounts of SiC and TiB2 can effectively enhance the mechanical properties of B4C ceramics while maintaining the lightweight characteristics critical for military and aerospace applications. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hot pressing and cold pressing on the superconducting properties of pyrene (C16H10) added bulk MgB2 were compared. For this aim, the polycrystalline disk-shaped MgB2 samples with addition of 4 wt % C16H10 powder were fabricated by a pellet/closed tube method at 850 °C, after hot pressing at 200 °C and cold pressing. The XRD and SEM results showed that although a-lattice parameters reduce for both C16H10 added samples, the average crystallite size increases after cold pressing because of the accumulation and inhomogeneous distribution of C in the MgB2 structure while it reduces for the C16H10 added hot pressed sample. The resistivity measurements showed that the increment of electron scattering is higher for the C16H10 added cold pressed sample than that of the C16H10 added hot pressed one which shows relatively better grain connectivity, and the Tc values of the samples are not appreciably affected by the pressing conditions. From the magnetisation measurements the in-field Jc values at 10 K and 5.5 T were obtained as 8.41 × 103 A/cm2, 1.62 × 104 A/cm2, 6.90 × 103 A/cm2 and the Hirr values while Jc = 100 A/cm2 at 20 K were obtained as 5.99 T, 6.55 T and 6.19 T for the pure sample and the C16H10 added hot and cold pressed samples, respectively. The higher Jc and Hirr values obtained for the C16H10 added hot pressed sample is because of the homogenous C substitution into MgB2 grains, as compatible with its lower Δρ value, and thus increased flux pinning ability. [ABSTRACT FROM AUTHOR]

This study examines the effect of cobalt on the crystallographic texture and grain boundary evolution of hot-press sintered tungsten heavy alloy (W-4.9Ni-2.1Cu). Traditional tungsten heavy alloy with a Ni:Cu ratio of 7:3 has cobalt added (i.e., cobalt content increased from 0 to 1 wt% with a 0.25 wt% interval). The samples were produced using the hot press sintering method with the following parameters: 50 MPa pressure, 10 °C/min heating rate, 1450 °C temperature, and a 20-min hold time. The unalloyed cobalt WHA compact has a fibre texture in the (001) plane that is aligned in the 〈111〉 orientation. In addition, the cobalt-alloyed WHAs compacts exhibit a lower proportion of grain boundaries with low angles. Enhanced solid solution formation between cobalt and WHAs during liquid phase sintering led to increased compacts densification and randomised weak fibre development in cobalt-alloyed compacts. Texture deterioration (001) <111> in cobalt-added WHAs is caused predominantly by substructural recovery during liquid phase sintering. This study indicates that the addition of cobalt to the stoichiometry of WHAs resulted in the homogenous distribution of binder matrix within the compact during sintering. As a result, the W-4.9Ni-2.1Cu-1Co alloy exhibited improved microhardness (429.5 HV0.5), electrical conductivity (23.34% of IACS), and relative density (98.10%). • The use of ball milling results in higher densification, faster solution re-precipitation kinetics during sintering. • Weakness in (001) <111> texture was attributed from the increase of cobalt stoichiometry in WHAs (W-4.9Ni-2.1Cu). • Enrichment of cobalt at the tungsten-binder matrix interface results in textural anisotropy in cobalt added WHAs. • Cobalt is an effective alloying addition for strengthening the WHA as evidenced by an increase of hardness and conductivity. [ABSTRACT FROM AUTHOR]

A new process of activating sizing film free (removed sizing) carbon fiber (SFF-CF) mats directly with electron beam irradiation (EBI) under oxygen-rich nitrogen gas prior to lamination assembly and hot-press was found to increase bending strength of CFRTP (CF reinforced thermoplastic polypropylene (PP)) interlayered composite composed of 3 SFF-CF mats between 4 PP sheets, [PP]4[SFF-CF]3. The hot-press fabrication was performed under 4.0 MPa at 473 K for 1 min. Experimental results showed optimal condition of 0.22 MGy-EBI under 2,000 ppm-O2-rich, protective N2 atmosphere improved bending strength, σ b at all accumulative probabilities, P f over that of untreated. This could be explained by maximum number of the strong covalent bonds of CF:C:C:PP and oxygen assisted CF:C:O:C:PP bonds adhering bare SFF-CF surface to PP, instead of the weak intermolecular bonding of CF(H2O, N2, O2)PP of untreated. The optimal concentration of O2 molecules together with the EBI probably purified the SFF-CF surface simultaneously generating dangling bonds, which already naturally exist in SFF-CF as evidenced by the highest intensity ESR peak whose inflection point was at B = 323 mT. This, along with attaching O groups to the SFF-CF surface can explain the increased SFF-CF to PP adhesion sites and bending strength increase. Fracture analysis showed the optimum condition prevented ply delamination and reduced damage area along sample length appearing to increase cohesion between the difficult to adhere thermoplastic PP and SFF-CF plies to take on higher loads. Although bending strength was increased, carefulness is always highly recommended when investigating unsized CF composites. [ABSTRACT FROM AUTHOR]

Our study mainly focused on diffusible hydrogen in aluminum-silicon-coated hot-stamped boron steel during a hot press forming process and in pre-treatment sequential lines of the automotive manufacturing process using a thermal desorption spectroscopy (TDS) technique. First, in the hot stamping procedure, as the soaking time increased in the heating furnace at a specific dew point when austenitizing, a high concentration of diffusible hydrogen was absorbed into the hot-stamped boron steel. Based on the TDS analysis of hydrogen absorbed from hot stamping, the activation energy value of hydrogen trapping in 1.8 GPa grade steel is lower than that of 1.5 GPa grade steel. This means that diffusible hydrogen can be more easily diffused into defective sites of the microstructure at a higher level of the tensile strength grade. Second, in sequential pre-treatment lines of the automotive manufacturing process, additional hydrogen did not flow into the surface, and an electro-deposition process, including a baking procedure, was effective in removing diffusible hydrogen, which was similar to the residual hydrogen of the as-received state (i.e., initial cold rolled blank). Based on these results, the hydrogen absorption was facilitated during hot press forming, but the hydrogen was sequentially desorbed during automotive sequential lines on aluminum-coated hot-stamped steel parts.

(85-x)WC–15 wt%Al 2 O 3 –xTiC (x = 0, 1.5, 2.5, 5, 10, and 20 wt%) composites were prepared by vacuum hot-press sintering. The influence of TiC addition on the corrosion behaviour of WC–Al 2 O 3 composites in 0.1 M NaOH solution was revealed. The results suggest that all the samples containing added TiC had the TiC phase and (W, Ti) C solid-solution phase, while the base composite had neither phase. With increasing added TiC content, the average grain size of WC decreased, and the relative density first increased and then decreased. Furthermore, the results suggest that the addition of TiC could noticeably increase the free corrosion potential and impedance and reduce the corrosion current density. However, the composite containing 20 wt% added TiC showed the opposite trend. Therefore, it can be concluded that the corrosion performance of the composites in an alkaline medium can be improved by adding an appropriate amount of TiC. The change in corrosion properties was caused by changes in the solid-solution phase, relative density, and TiO 2 oxide film. [ABSTRACT FROM AUTHOR]

Thermal crush burn injury due to roller type ironing press machine is relatively rare and can cause destructive effects with significant morbidity. These injuries can be avoided by taking some basic precautions. Early debridement after admission and definitive treatment after the extent of injuryare delineated and these are the preferred approaches in the management. We present a case of thermal crush injury of the hand caused by laundry roller type ironing press machine.

In Al-Si-coated hot-press-forming (HPF) steels, high reactivity between Al and moisture often leads to the generation of hydrogen (H) atoms at elevated temperatures, resulting in hydrogen embrittlement. In this study, a thin Ni layer of approximately 0.5 μm in thickness was electroplated on the steel substrate surface before the conventional Al Si coating process. The formation of a Ni-enriched zone was found to affect hydrogen intrusion and emission behavior positively. Prior to the HPF simulation, the Ni-enriched zone was formed inside Fe 2 SiAl 7 intermetallic compounds, and migrated toward the outer FeAl(Si) layer during the subsequent HPF simulation. This migration served as an impediment to elemental diffusion, thereby resulting in a prolonged simulation time for the complete formation of coating microstructures. Consequently, the presence of the Ni-enriched zone functioned as a high-energy barrier, impeding the diffusion of H and rendering H intrusion more challenging, while simultaneously enhancing corrosion resistance. Complete H emission occurred within 3 days in the Ni-precoated sheet, whereas a significant amount of H content remained even after 17 days in the non-Ni-precoated sheet. This difference could be attributed to the reduced amount of H intrusion in the Ni-precoated sheet, despite similar H emission rates observed in both sheets. [Display omitted] • Ni-precoating decreases Kirkendall voids. • Ni-precoated Al-Si-coated HPF steel exhibits less hydrogen penetration. • Ni-precoated Al-Si-coated HPF steel demonstrates superior corrosion resistance. [ABSTRACT FROM AUTHOR]

We fabricated boron carbide-silicon carbide (B 4 C–SiC) composites by hot-press sintering without additives and evaluated the crystal phase, relative density, microstructure, and mechanical properties of the sintered body. When B 4 C and SiC were uniformly dispersed in the composite, crystal growth was inhibited, and a sintered body with a fine and uniform microstructure, with improved mechanical properties, was fabricated. The relative density of B 4 C–SiC composites sintered at temperatures lower than 2000 °C and 40 MPa of pressure exceeded 99.8%, and the bending strength and Vickers hardness at B 4 C 50 wt% were 645 MPa and 30.6 GPa, respectively. [ABSTRACT FROM AUTHOR]

In our research work, we are focusing on bamboo due to its advantages of fast growth, renewability, flexibility, low cost, and high specific strength and stiffness which can be frequently compared with glass fiber. We have proposed a novel hot press fabrication method of binder-free green composite products made of bamboo fibers extracted by end-milling with a machining center. Lignin could serve as a bonding material to make the bamboo fiber self-bonded itself by hot press forming to fabricate our green composite from pure 100% bamboo fiber without any binder materials because its extracted fibers are hardly damaged with a machining center. In our previous studies, we have developed a hot press forming method to fabricate two-dimensional small and simple shape products based on bamboo fiber self-bonded technology. In the present report, we propose a novel two-step hot press forming method based on two kinds of dies to fabricate three-dimensional shape products. Especially, we focus on hemisphere shell shape products because a hemispherical conical cup press forming test is frequently used to estimate the press forming performance of a kind of complex plate products. As a result, the proposed two-step concept of hot press forming is found to be effective to fabricate the three-dimensional shell shape product made of pure 100% bamboo fibers. It can be also seen that a suitable treatment between first and second step is considered important because it aids effective action due to liquid flow performance and the plastic zone of molding material.

Graphite/copper composites have great potential for tribological applications because of their high thermal and abrasion resistance. In this study, we successfully manufactured graphite/copper composites that demonstrated superior thermal conductivity and wear resistance by employing microwave hot press sintering (MHPS). The results demonstrated an enhancement in the density and hardness of the composites as the graphite particle size increased, owing to the influence of MHPS. Meanwhile, the graphite/copper composite with a graphite particle size of 300 µm has excellent thermal conductivity and friction properties, with a thermal conductivity of up to 679.5 W/mK and a wear rate of only 3.019 10−6 cm3/(N · m). The work is expected to provide a new route for the developing highly thermally conductive and abrasion-resistant materials. [ABSTRACT FROM AUTHOR]

In aerospace and automotive industries, hot press forming (HPF) technology is widely used for rapid and precise deformation of the complex sheet metal component, where the fracture behavior has always been a focused problem. In this study, the hot tensile test and the Nakazima test were carried out, in order to establish the Misiolek constitutive equation and determine the forming limit strain points at an elevated temperature, respectively. The microstructure evolution during the tensile test was also investigated by optical microscope. In addition, the Marciniak⁻Kuczynski (M⁻K) model, considering the Mises, Hill48, and Logan⁻Hosford yield criteria, was utilized to calculate the theoretical forming limit curve (FLC). Furthermore, the fracture behavior of the TA32 alloy sheet during the HPF process was accurately predicted by inserting the predicted FLC into finite element simulation, and the qualified complex component was obtained by optimizing the shape of the sheet.

To produce samples for both material testing and molded sheets/parts, this article details an open-source scientific cold and hot press design. It consists of two independent and modular upper and lower plate (929 cm2) assemblies each containing four 125 W insulated steel strip heaters. The steel housing for these heaters is entirely modular and designed for ease of manufacture, assembly, and customization. This system allows a researcher with access to a hydraulic press to repurpose existing equipment into a multipurpose hot and cold press, or if an independent machine is warranted, an additional welded support frame and commercially available bottle jack offer standalone operation. By utilizing this small-scale hot press either in conjunction with a hydraulic press or on its own, samples can be produced to determine the critical material properties of any polymer, composite, or polymer blend. A series of modular molds allow for the rapid production of flat sheet stock and solid testing samples adhering to the ASTM D695 standard for rigid plastics tested in compression and ASTM D638 standard for testing plastics in tension. The sheet mold offers the user the ability to produce stock sheets that can be cut and assembled into 2.5-D applications with post processing.

Sintering is a critical process for the preparation of metallic matrix diamond tools. The purpose of this work aims to propose a novel microwave hot-press sintering (MHPS) method for the improvement of mechanical properties for Fe-Cu-W-Sn matrix diamond tools. The samples were prepared by MHPS and conventional hot-press sintering (CHPS), respectively. The microstructures of samples were characterized using XRD, EMPA, and SEM tests. The mechanical properties of samples, such as relative density, hardness, bending strength, and impact toughness were also investigated. Experimental results show that the samples by MHPS method has obvious advantages with shorter sintering time, lower sintering temperature, more uniform element diffusion, and better holding situation of diamond abrasives in the alloyed matrix. The optimal mechanical properties of samples sintered by MHPS at 850 °C, to be specific, including relative density, hardness and flexural strength reach 97.8%, 99.2 HRB and 986 MPa, respectively. The possible mechanism of MHPS is discussed. This work can provide a reference for microwave sintering of metallic matrix diamond tools. [ABSTRACT FROM AUTHOR]

This work addresses the results of experimental investigation carried out on mechanical and morphological properties of plain woven kenaf fiber reinforced PVB film which was prepared by hot press technique. The composites were prepared with various fiber contents: 0%, 10%, 20%, 30%, 40%, 50%, and 60% (by weight), with the processing parameters 165°C, 20 min, and at a pressure of 8 MPa applied on the material. Tensile, flexural, and Charpy impact properties were studied as well as morphological properties of impact fracture surface. With the increase in kenaf fibers content up to 40%, the PVB composites have shown lower tensile and flexural strength accompanied with reduction in the ultimate strain of the composite. The results showed that impact properties were affected in markedly different ways by using various kenaf contents and decrease with the increase in kenaf fiber content up to 40%; however, high impact strength was observed even with 40% kenaf fiber content. Furthermore, scanning electron microscopy for impact samples was utilised to demonstrate the different failures in the fracture surfaces for various kenaf fibers contents.

Bamboo macromolecules were pretreated with bamboo vinegar, which has an antibacterial property, and processed into antibacterial bioboard (ABB) by hot pressing. The ABB was then analyzed by conducting Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential thermal analysis. Results showed that ABB samples had average density of 1.0 g/cm 3 , which is appropriate for application. The physical and mechanical properties were best for the ABB sample pretreated with bamboo vinegar and hot pressed at 165 °C for 10 min. Fourier-transform infrared spectroscopy revealed that the optimum conditions for hot pressing were a temperature of 165 °C, duration of 10 min, and the addition of bamboo vinegar. Thermogravimetric analysis/differential thermal analysis curves indicated that the thermal degradation of the ABB was less than that of bamboo, revealing that hot pressing increased the thermal stability of ABB samples. Analysis revealed that pretreatment with bamboo vinegar improved the antibacterial property of the ABB. [ABSTRACT FROM AUTHOR]