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The application of magnesium oxychloride cement (MOC) is promising, but its poor water resistance seriously hinders its development and application. In this paper, we describe a new type of MOC with excellent water resistance, prepared using fly ash and hexadecyltrimethoxysilane (HDTMS). SEM, XRD, FTIR, TG/DSC, and other microscopic-scale studies were conducted to investigate the mechanism underlying the water-resistance enhancement of the new MOC. It was found that adding 20% fly ash and 3% HDTMS can strengthen the water resistance of MOC while retaining high mechanical properties. In particular, the residual coefficient remained at 0.91 after 7 days of immersion. This is because these two additives, when used together, can increase the content of the gelling 5-phase of MOC, as well as optimize the pore structure of MOC.

This study investigated the effects of the replacement ratio of natural aggregates (NAs) by recycled aggregate (RAs), the replacement ratio of cement by rice husk ash (RHA), and their interaction on compressive properties of recycled aggregate concrete (RAC). The RAs used consisted of 37.5 wt% recycled brick aggregates and 62.5 wt% recycled concrete aggregates from construction and demolition waste. To optimise the properties of RAC mixture, a full factorial design of experiment was applied in designing the concrete mixture proportion. The two factors considered were: the replacement ratio (wt.%) of RA with five levels (0%, 30%, 50%, 70% and 100%) and the replacement ratio (wt.%) of RHA with four levels (0%, 10%, 20% and 30%). Axial compression tests based on the full factorial experiment were conducted on cubic and prismatic samples at 28 days to evaluate their compressive properties. In addition, further cubic concrete groups were also tested in axial compression at different concrete ages (i.e., 3, 7, 28, 56 and 91 days) to understand the effect of concrete age on the compressive strength. Statistical analyses including ANOVA, post-hoc pairwise comparisons and effect size (Cohen's d) computation were performed to evaluate the experimental results. The results indicated that the compressive strength of concrete at 28 days was significantly affected by the replacement ratio of RA and RHA (both p-values

AlCrFeNiCuWx high entropy alloys were fabricated on 316 L stainless steel substrate using laser metal deposition technique. The microstructural and mechanical characteristics of these alloys were studied by advanced characterization techniques. The results revealed that the alloys exhibited a dual phase structure with BCC (body centered cubic) and FCC (face centered cubic) solid solution phases. The presence of tungsten (W) particles in the HEA matrix changed the shape of grains from columnar to aquiaxed. The alloys that contained W possessed higher plasticity at maximum compressive stress. They also showed better performance when they were evaluated for wear and corrosion.

Climate change makes it imperative to use materials with minimum global warming potential. The fourth-generation blowing agent HCFO-1233zd-E is one of them. The use of HCFO allows the production of polyurethane foam with low thermal conductivity. Thermal conductivity, like other foam properties, depends not only on the density but also on the cellular structure of the foam. The cellular structure, in turn, depends on the technological parameters of foam production. A comparison of pouring and spray foams of the same low density has shown that the cellular structure of spray foam consists of cells with much less sizes than pouring foam. Due to the small size of cells, spray foam has a lower radiative constituent in the foam conductivity and, as a result, a lower overall thermal conductivity than pouring foam. The water absorption of spray foam, due to the fine cellular structure, also is lower than that of pouring foam. Pouring foam with bigger cells has higher compressive strength and modulus of elasticity in the foam rise direction. On the contrary, spray foam with a fine cellular structure has higher strength and modulus in the perpendicular direction. The effect of foam aging on thermal conductivity was also studied.

The effect of aluminum (0, 2, 4, and 6 wt. %) and copper (0, 2, 4, and 6 wt. %) on graphite morphology, microstructure and compressive behavior of ductile iron specimens manufactured by sand casting technique were investigated. The graphite morphology and microstructure were evaluated using optical microscopy (OM) and scanning electron microscopy (SEM) equipped image processing software. To study the mechanical properties, the compression test was conducted on the ductile iron specimens. The results indicated that the surface fraction and nodule count of graphite decreased when the amount of aluminum increased from 0 to 2 wt. % and after that from 2 to 6 wt. %. In addition, the nodularity of graphite increased with the increment of the aluminum amounts. By adding the amount of copper, the surface fraction and nodule count of graphite increased and nodularity of graphite decreased. The addition of aluminum and copper decreased the surface fraction of ferrite and increased the surface fraction of pearlite in the microstructure. By increasing the amounts of aluminum and copper, compressive stress vs. strain curves were shifted upwards, and modulus of elasticity, yield strength, maximum compressive stress, and fracture strain improved. In comparison with copper, aluminum had a greater influence on the mechanical properties of ductile iron.

Epoxy polymer composites embedded with thermally conductive nanofillers play an important role in the thermal management of polymer microelectronic packages, since they can provide thermal conduction properties with electrically insulating properties. An epoxy composite system filled with graphitic-based fillers; multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs) and ceramic-based filler; silicon carbide nanoparticles (SiCs) was investigated as a form of thermal-effective reinforcement for epoxy matrices. The epoxy composites were fabricated using a simple fabrication method, which included ultrasonication and planetary centrifugal mixing. The effect of graphite-based and ceramic-based fillers on the thermal conductivity was measured by the transient plane source method, while the glass transition temperature of the fully cured samples was studied by differential scanning calorimetry. Thermal gravimetric analysis was adopted to study the thermal stability of the samples, and the compressive properties of different filler loadings (1–5 vol.%) were also discussed. The glass temperatures and thermal stabilities of the epoxy system were increased when incorporated with the graphite- and ceramic-based fillers. These results can be correlated with the thermal conductivity of the samples, which was found to increase with the increase in the filler loadings, except for the epoxy/SiCs composites. The thermal conductivity of the composites increased to 0.4 W/mK with 5 vol.% of MWCNTs, which is a 100% improvement over pure epoxy. The GNPs, SiCs, and MWCNTs showed uniform dispersion in the epoxy matrix and well-established thermally conductive pathways.

An expandable rigid PU foam can turns into complex shapes, with a shell like structure on the outside and honeycomb structure on the inside, which can be easily shaped to a vertebra form. The present study aims to determine whether expandable rigid polyurethane foam was an appropriate substitute for rigid block polyurethane foam to model the trabecular bone. Static compression tests were performed to determine compressive moduli and yield stresses on three polyurethane foam densities namely 0.16 g/cm3, 0.24 g/cm3 and 0.42 g/cm3. Morphology of the PU foams for all densities was also observed. The compressive modulus for 0.16 g/cm3 and 0.24 g/cm3 were found varied from 40 to 43 MPa and 83 to 92 MPa while yield stress ranged from 2.1 to 2.3 MPa and 3.4 to 4.8 MPa respectively. As for 0.42 g/cm3, the compressive modulus and yield stress varied from 240 to 256 MPa and 38 to 40 MPa. Based on these results, the compressive modulus and yield stress of 0.24 g/cm3 compared favourably with rigid block PU foam and human cadavers presented in the literatures. Hence, the findings of this study could potentially be used in developing a synthetic vertebral trabecular bone of paediatric spine for biomechanical testing. Keywords: Polyurethane foam, Synthetic spine, Trabecular bone, Compressive properties

In this study, the Zn-0.8Mg-0.28CaO wt.% composite was successfully prepared using different conditions of ball milling (rotations and time) followed by a direct extrusion process. These materials were characterized from the point of view of microstructure and compressive properties, and the correlation between those characteristics was found. Microstructures of individual materials possessed differences in grain size, where the grain size decreased with the intensified conditions (milling speed and time). However, the mutual relation between grain size and compressive strength was not linear. This was caused by the effect of other factors, such as texture, intermetallic phases, and pores. Material texture affects the mechanical properties by a different activity ratio between basal and pyramidal slips. The properties of intermetallic particles and pores were determined in material volume using micro-computed tomography (µCT), enhancing the precision of our assumptions compared with commonly applied methods. Based on that, and the analysis after the compressive tests, we were able to determine the influence of aspect ratio, feret diameters, and volume content of intermetallic phases and pores on mechanical behavior. The influence of the aspects on mechanical behavior is described and discussed.

In order to solve the difficulties in the utilization of aluminum dross resources, non-fired bricks with aluminum dross with high nitrogen concentration as the main raw material were prepared. Three process parameters, including forming pressure, mixing-water amount, and aluminum dross particle size, were subjected to single-factor experiments. Based on the response surface method, a mathematical model was established between the process parameters and the non-fired bricks’ compressive properties, which were subjected to ANOVA. The process parameters were optimized and then verified experimentally. According to the results, the established regression model is able to accurately predict the compressive properties of non-fired bricks. The difference between the experimental value and the model’s predicted value was only 0.36%. The optimal process parameters for aluminum dross to prepare non-fired bricks are as follows: forming pressure is 18 MPa, mixing-water amount is 15% and particle size range is 80–130 mesh. The compressive strength of the prepared non-fired bricks is 24.66 MPa, which meets the requirement of MU20 non-fired bricks in Non-fired Rubbish Gangue Bricks.

There is an inevitable trend toward exploring new, environmentally friendly fibers that can be used as raw material for mattresses with moderate hardness and air-permeable characteristics. Ethylene-propylene side by side (ES), high-shrinkage fibers, and thermoplastic polyester elastomer (TPEE) chips were introduced into polyethylene glycol terephthalate (PET)/polybutylene terephthalate (PBT) chip by melt blending to modify PET/PBT fiber. The modified PET/PBT (hereinafter referred to as PLON) is more suitable for mattress filling material than PET/PBT. To explore the compressive properties of PLON cushion made of PLON fiber and expand the scope of the PLON cushion’s application, a layered hardness test, hardness classification test and variance analysis were used to comprehensively evaluate the surface hardness, core hardness, bottom hardness and hardness classification of the mattress made of PLON cushion. The conclusions are: (1) The materials of the support layer have a significant effect on the hardness grade S. The hardness of the mattress with PLON as the support layer is between the spring and the coir; (2) when PLON is used as the material of the support layer, it possesses higher supporting force than coir and the characteristics of light weight and high resilience, which coir does not have; it is also softer than a spring mattress. As cushion material, it provides higher support for mattresses than foam. Practical applications, densities and structure were clarified through the above research, with implications for broader applications for PLON blocks in mattress products.

The compressive deformation behavior of the as-cast and as-extruded MgYNi (at.%) alloy mostly composed of long period stacking ordered (LPSO) phase was studied by in-situ synchrotron radiation combined with the analysis of deformation traces after compression at different applied stress. The as-cast alloy has random texture, while the as-extruded alloy has a typical basal texture with basal plane parallel to extrusion (compression) direction. Prior to macro-yielding, some softly oriented grains are preferentially plastically deformed, leading to micro-yielding. The micro-yielding behavior of both as-cast and as-extruded alloys is controlled by basal slip, the as-extruded alloy has higher micro-yielding strength than the as-cast alloy. The activated deformation mode near the macro-yielding point is prismatic slip in both as-cast and as-extruded alloys, and as the hard oriented grains dominate in the as-extruded alloy, the compressive yield strength of the alloy is increased from 217 MPa to 535 MPa after extrusion. The kinking activated following the prismatic slip can introduce a large number of dislocations in the as-extruded alloy, resulting in high strain-hardening rate of 3000 MPa, high ultimate compressive strength of ∼800 MPa and plastic strains above 10%., This work was supported by National Natural Science Foundation of China (No. U21A2047, No. 51971076 and No. 52001069). The Deutches-Elektronen-Synchrotron (DESY) is acknowledged for the provision of the beamtime at P07B-HEMS beamline of PETRA III.

Currently, polyurethane (PU) production is completely dependent upon fossil oil, as the two primary reagents necessary for PU production, polyol and isocyanate, are derived from fossil fuels. Eucalyptus branches are waste products for most forest management companies. In this work, polyols obtained by the liquefaction of eucalyptus branches were used for foam production. The influence of the isocyanate, catalyst, surfactant, and blowing agent contents on the foam properties was studied. Overall the amount of each chemical used in the production of PU foams had a noticeable effect on the density and compressive properties. The amount of water (blowing agent) had the strongest effect and decreased the density and compressive properties because of higher foam expansion. The other chemicals increased or decreased the density and compressive stress depending on the amount used. The density of the produced foams ranged from 36 kg/m3 to 108 kg/m3, the compressive stress ranged from 15 kPa to 149 kPa, and the Young’s modulus ranged from 64 kPa to 2100 kPa. The results showed that it is possible to convert these forest residues into PU foams with properties somewhat similar to those of commercial foams, although with a lower compressive strength. info:eu-repo/semantics/publishedVersion

It is known that 3D-printed PETG composites reinforced with carbon or Kevlar fibres are materials that can be suitable for specific applications in the aeronautical and/or automotive sector. However, for this purpose, it is necessary to understand their mechanical behaviour, which is not yet fully understood in terms of compression. Therefore, this study intends to increase the knowledge in this domain, especially in terms of static behaviour, as well as with regard to creep and stress relaxation due to the inherent viscoelasticity of the matrix. In this context, static, stress relaxation and creep tests were carried out, in compressive mode, using neat PETG and PETG composites reinforced with carbon and Kevlar fibres. From the static tests, it was found that the yield compressive strength decreased in both composites compared to the neat polymer. Values around 9.9% and 68.7% lower were found, respectively, when carbon and Kevlar fibres were added to the PETG. Similar behaviour was observed for compressive displacement, where a reduction of 20.4% and 46.3% was found, respectively. On the other hand, the compressive modulus increased by 12.4% when carbon fibres were added to the PETG matrix and decreased by 39.6% for Kevlar fibres. Finally, the stress relaxation behaviour revealed a decrease in compressive stresses over time for neat PETG, while the creep response promoted greater compressive displacement. In both situations, the response was very dependent on the displacement/stress level used at the beginning of the test. However, when the fibres were added to the polymer, higher stress relaxations and compressive displacements were observed.

The addition of Nb can form a eutectic phase with a NiTi matrix in a NiTi-based shape memory alloy, improving the transition hysteresis of the NiTi alloy. A Ni44Ti44Nb12 ingot was prepared using the vacuum induction melting technique. Under compression deformation, the yield strength of the NiTi–Nb alloy is about 1000 MPa, the maximum compressive strength and strain can reach 3155 MPa and 43%, respectively. Ni44Ti44Nb12 exhibited a superelastic recovery similar to that of the as-cast NiTi50. Meanwhile, the loading–unloading cycle compression shows that the superelastic recovery strain reached a maximum value (2.32%) when the total strain was about 15%, and the superelasticity tends to rise first and then decrease as the strain increases.

The additive manufacturing (AM) of carbon fiber reinforced plastic (CFRP) composites continue to grow due to the attractive strength-to-weight and modulus-to-weight ratios afforded by the composites combined with the ease of processibility achievable through the AM technique. Short fiber design factors such as fiber content effects have been shown to play determinant roles in the mechanical performance of AM fabricated CFRP composites. However, this has only been investigated for tensile and flexural properties, with no investigations to date on compressive properties effects of fiber content. This study examined the axial and transverse compressive properties of AM fabricated CFRP composites by testing CF-ABS with fiber contents from 0%, 10%, 20%, and 30% for samples printed in the axial and transverse build orientations, and for axial tensile in comparison to the axial compression properties. The results were that increasing carbon fiber content for the short-fiber thermoplastic CFRP composites slightly reduced compressive strength and modulus. However, it increased ductility and toughness. The 20% carbon fiber content provided the overall content with the most decent compressive properties for the 0–30% content studied. The AM fabricated composite demonstrates a generally higher compressive property than tensile property because of the higher plastic deformation ability which characterizes compression loaded parts, which were observed from the different failure modes.

The primary advantage of lattice structures over other cellular structures is the possibility of obtaining higher mechanical properties combined with lower weight. This paper describes the quasi-static mechanical behaviour of eight lightweight lattice structures of various tessellated unit cell topologies using finite element (FE) analysis. Three types of structures were additively manufactured with polyamide (PA12) material using the advanced Multi Jet Fusion technology and were tested under quasi-static compressive loading. The experimental results were used to validate the FE models of the lattices. We compared specific mechanical properties of all eight structures designed with an identical strut diameter of 1 mm or an identical relative density of 0.095. Such comparisons provide a different order of preference for the lattice structures. Based on Maxwell’s stability criterion, the current eight structures are of bending-dominated nature; however, these structures may exhibit stretch-dominated behaviour due to a reasonable amount of struts aligned in the direction of the external load. An excellent combination of stiffness, strength, and energy absorption can be obtained by the structures, when the load is applied in a specific direction with respect to the strut elements.

The influence of microstructure, heat treatment and alloying addition on mechanical and fracture properties of Ti3Al-based intermetallic at room and elevated temperatures was studied. Ti3Al-11Nb-1Mo (mole fraction, %) alloy was consolidated via powder metallurgy processing by mechanical alloying (MA) and hot pressing (HP). MA powders were characterized using XRD and SEM-EDS. Optimum MA duration was 25 h and HP conditions of 1350 degrees C, 2 h, 35 MPa. After HP, solution treatment at 1050 degrees C for 1 h and water quenching alpha(2)+beta WidmanstAtten microstructure is present, while subsequent aging at 800 degrees C during 24 h induces small content of O-phase. High fraction of beta-phase is a direct consequence of Mo. Compression tests were performed from room temperature to 750 degrees C in vacuum. The yield strength of compacts increases with temperature up to 250 degrees C (pyramidal slip systems activation), after which it decreases. Ductility increases throughout the whole temperature range. The presence of O phase contributed to ductility increase in aged alloys, while negligibly lowering yield strength. Registered drop in the yield strength of aged alloys compared with non-aged ones was mostly influenced by precipitation of a. 2 particles. Mixed fracture modes are operative at all temperatures.

High-entropy alloys (HEAs) have attracted a great deal of interest over the last 14 years. One reason for this level of interest is related to these alloys breaking the alloying principles that have been applied for many centuries. Thus, HEAs usually possess a single phase (contrary to expectations according to the composition of the alloy) and exhibit a high level of performance in different properties related to many developing areas in industry. Despite this significant interest, most HEAs have been developed via ingot metallurgy. More recently, powder metallurgy (PM) has appeared as an interesting alternative for further developing this family of alloys to possibly widen the field of nanostructures in HEAs and improve some capabilities of these alloys. In this paper, PM methods applied to HEAs are reviewed, and some possible ways to develop the use of powders as raw materials are introduced.

The microstructure, Vickers hardness, and compressive properties of novel low-activation VCrFeTaxWx (x = 0.1, 0.2, 0.3, 0.4, and 1) high-entropy alloys (HEAs) were studied. The alloys were fabricated by vacuum-arc melting and the characteristics of these alloys were explored. The microstructures of all the alloys exhibited a typical morphology of dendritic and eutectic structures. The VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys are essentially single phase, consisting of a disordered body-centered-cubic (BCC) phase, whereas the VCrFeTa0.2W0.2 alloy contains fine, nanoscale precipitates distributed in the BCC matrix. The lattice parameters and compositions of the identified phases were investigated. The alloys have Vickers hardness values ranging from 546 HV0.2 to 1135 HV0.2 with the x ranging from 0.1 to 1, respectively. The VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys exhibit compressive yield strengths of 1341 MPa and 1742 MPa, with compressive plastic strains of 42.2% and 35.7%, respectively. VCrFeTa0.1W0.1 and VCrFeTa0.2W0.2 alloys have excellent hardness after annealing for 25 h at 600&ndash, 1000 &deg, C, and presented compressive yield strength exceeding 1000 MPa with excellent heat-softening resistance at 600&ndash, 800 &deg, C. By applying the HEA criteria, Ta and W additions into the VCrFeTaW are proposed as a family of candidate materials for fusion reactors and high-temperature structural applications.

Microstructural evolution and compressive properties of two-phase Nb-Fe binary alloys based on the C14 Laves phase NbFe2 were characterized at both the hypo- and hypereutectic compositions. The experimental results indicated that the microstructures of the two alloys consisted of fully eutectics containing Fe and NbFe2 phases at the bottom of the ingots corresponding to the largest solidification rates. With the decrease of solidification rate, the microstructures developed into primary Fe (NbFe2) dendrites plus eutectics in the middle and top parts of the ingots. The microstructural evolutions along the axis of the ingots were analyzed by considering the competitive growth between the primary phase and eutectic as well as using microstructure selection models based on the maximum interface temperature criterion. Furthermore, the compressive properties of the two alloys were measured and the enhancements were explained in terms of the second Fe phase and halo toughening mechanisms.

Drilling is used in creating cylindrical through-holes for various applications. While optimizing drilling parameters is widespread, the effect of a drilled through-hole on the structural stability of components is not fully documented. The base material, along with other parameters, such as drill diameter, drill location and its orientation affect structural stability. Since carrying out tests on different base materials can be time consuming, simulation software can instead be used to provide valuable information. However, the comparison between experiments and simulations gets difficult, hence, this study attempts to provide a basis for effective comparison by studying simulations and compression tests, comparing the two, and documenting the role of drill hole orientation on the compressive response of magnesium, a material with immense potential in light-weight components. Simulations and experiments were carried out on three through-hole orientations and were compared to the undrilled scenario. Results demonstrate significant differences in compression behaviour. While the compressive yield strength increased in all three drill orientations, ultimate strength and ductility was reduced in horizontal and angular drill hole orientations. These observations, therefore, provide valuable insight into choosing the right orientation for different applications.

Polylactide (PLA), a biopolymer, was reinforced with three fillers (two organic reinforcements and one inorganic filler). The processing technique used to fabricate the composites was the melt-blending technique. The composites and the unreinforced PLA were subjected to microhardness, compression and biodegradation characterisations. Data obtained are presented in this article as raw data. Data from microhardness and compression tests were used to predict the fracture toughness. The biodegradation of the composites was also examined, and the data obtained reported in this article. The data presented in this article allow for a comprehensive understanding of the mechanical behaviour and the biodegradation profile of three composites of PLA with respect to their applications as biodegradable implants. It also helps in the selection of fillers for biopolymers such as PLA.

We developed novel Ti-Zr-Be-Co bulk metallic glasses through Co addition based on a ternary Ti45Zr20Be35 alloy. By altering the alloying routes and alloying contents, the influence of Co alloying on glass-forming ability, thermal stability, thermoplastic formability, crystallization behavior, and corrosion resistance has been investigated systematically. It was found that the best alloying route for enhancing the glass-forming ability, thermoplastic formability, compressive plasticity, and corrosion resistance is to replace Be by Co. Ti45Zr20Be23Co12 possesses the largest critical diameter of 15 mm for glass formation. Ti45Zr20Be27Co8 possesses the highest thermoplastic formability which is comparable to that of Vitreloy alloys. Ti45Zr20Be25Co10 exhibits the largest room temperature plasticity of 15.7% together with a high specific strength of 3.90 &times, 105 Nm/kg. The addition of Co also strongly affects the crystallization behavior of the base alloy, resulting in a more complex crystallization process. The corrosion resistance of Ti-Zr-Be alloy in 1 mol/L HCl solution can also be enhanced by Co alloying. The related mechanisms have been explained in detail, which provide guidance for the composition design of Ti-based metallic glasses with improved properties.

The addition of Nb can form a eutectic phase with a NiTi matrix in a NiTi-based shape memory alloy, improving the transition hysteresis of the NiTi alloy. A Ni44Ti44Nb12 ingot was prepared using the vacuum induction melting technique. Under compression deformation, the yield strength of the NiTi&ndash, Nb alloy is about 1000 MPa, the maximum compressive strength and strain can reach 3155 MPa and 43%, respectively. Ni44Ti44Nb12 exhibited a superelastic recovery similar to that of the as-cast NiTi50. Meanwhile, the loading&ndash, unloading cycle compression shows that the superelastic recovery strain reached a maximum value (2.32%) when the total strain was about 15%, and the superelasticity tends to rise first and then decrease as the strain increases.

The study reports the measured effects of water absorption on an epoxy resin. Epoxy samples were exposed to wet conditioning environments including pure water, NaCl-water solution, and pure water at boiling temperature, measuring absorption as a function of time. Vickers hardness and indentation creep tests were performed and the mechanical response of the material to uniaxial stress was also measured in both compression and tension, at imposed strain rates in the range 0.001–2500 s−1. It was found that the absorption of both pure and salt water caused decrease of stiffness, yield stress and hardness, but only mildly affected the sensitivity of the response to the imposed strain rate and the tensile ductility. Mechanical testing after re-drying of the samples revealed the permanent effects of water absorption.

The variation of the density and compressive properties through a single closed-cell aluminium alloy foam block were evaluated. For this purpose a rectangular block of aluminium foam was fabricated and cut into identical small cubic representative volume specimens in three horizontal layers (bottom, middle and top). The mechanical characteristics of these cubic representative volume specimens were determined using quasi-static and dynamic compression tests, parallel and perpendicular to the foaming direction. The visual observation of the cubic representative volume specimens revealed that the pore size and the relative density vary across the original foam block, particularly on the different horizontal layers. Accordingly, the variation of the compressive properties and the energy absorption characteristics also proved to be significant.

The microstructural evolution and room-temperature mechanical properties of Fe50Al50-nNbn alloys (n=1, 3, 5, 7, and 9 at%) were investigated after solidification and subsequent heat treatment. For all the compositions, the (Fe, Al)(2)Nb Laves phase formed because of the incomplete solid solubility of Nb in the Fe-Al-based phases and tended to develop an eutectic mixture with the Fe-Al-based phase. According to the results of EDS analysis and microstructural investigations, the Nb concentration of the eutectic composition was 9 at%, and the solid solubility of Nb in the B2-type Fe-Al-based phase was 3 at%. In addition, the eutectic phase transition temperature was approximately 1265 degrees C. Compared with the as cast state, all the heat-treated alloys exhibited ultrahigh compressive strength and considerably increased compressive fracture strains. The heat-treated hypoeutectic Fe50Al42Nb3 alloy exhibited the highest compressive strength and fracture strain of 3.02 GPa and 33.1%, respectively, and the eutectic Fe(50)oAl(41)Nb(9) alloy exhibited the lowest compressive strength and fracture strain of 2.66 GPa and 21.8%, respectively, because of the absence of the comparably softer Fe-Al-based primary dendrites. The superior mechanical properties of the heat-treated alloys were attributed to the bimodal distribution of the microstructure, structural incoherency between the crystalline phases, and elimination of solidification artifacts and lattice defects.

The lotus-type porous copper with various pore structural parameters was fabricated by a novel solid-gas eutectic solidification process (the Gasar process). The effects of porosity and the Angle between load direction and pores axis (ALP) on compressive behaviours of porous copper were investigated. The results show that the compressive stress-strain curves vary with porosity and compressive direction. Under the same compressive direction, as the porosity increases, the compressive yield strength of the porous copper decreases. The compressive properties of the porous copper show obvious anisotropy, and the yield strength of the porous copper decreases with increasing the angle between pore axis and compressive direction. The Deformation mechanisms analyzed by finite element simulation (FES) are well consistent with experiment process for the samples with ALP of 0° and 90°.

The effect of montmorillonite clay on the compressive properties of Epikote 828 epoxy was studied. A series of epoxy-based nanocomposites with 1-5 wt.% nanoclay content was prepared. The degree of dispersion and exfoliation was investigated using transmission electron microscopy. Static uniaxial compression tests were conducted in order to study the effect of nanoclay on the compressive stress-strain behaviour and compressive properties of the Epikote 828 polymer. It was found that the compressive properties depend on the degree of exfoliation of the clay nanoplatelets in the epoxy. Reduction in compressive strength for 1 and 3 wt% nanoclay was recorded. This is because the intercalated structure of nanoclay in the polymer creates high localised stresses in the matrix during compression that leads to premature failure.

The Al-TiAl3 compound materials were prepared by depositing molten Al droplets onto the Ti powders layer at 350 °C. The results show that the stoichiometric TiAl3 phase is the only Ti-Al intermetallic compound formed during the reaction process. The microstructure analysis shows that the TiAl3 particles disperse in an Al matrix. The results of the compressive tests of the specimens at room temperature show that the reacted Al-TiAl3 compound has higher compressive strength of 594.7 MPa and fracture strain of 13.5 %.

Investigations on high strain rate behavior of epoxy LY 556 under compressive loading are presented. Compressive Split Hopkinson Pressure Bar (SHPB) apparatus was used for the experimental investigations. The studies are presented in the strain rate range of 683-1890 per second. It was generally observed that the compressive strength is enhanced at high strain rate loading compared with that at quasi-static loading. During SHPB testing of the specimens, it was observed that the peak force obtained from the strain gauge mounted on the transmitter bar is lower than the peak force obtained from the strain gauge mounted on the incident bar. Further, an analytical method is presented based on variable rate power law for the prediction of compressive strength at high strain rate loading for epoxy LY 556. Using the analytical method, high strain rate compressive stress-strain behavior is presented up to strain rate of 10,000 per second. (C) 2010 Elsevier B.V. All rights reserved.

Microstructural observations and compressive property datasets of metal matrix syntactic foam core sandwich composite at quasi-static and high strain rate (HSR) conditions (525–845s−1) are provided. The data supplied in this article includes sample preparation procedure prior to scanning electron and optical microscopy as well as the micrographs. The data used to construct the stress–strain curves and the derived compressive properties of all specimens in both quasi-static and HSR regions are included. Videos of quasi-static compressive failure and that obtained by a high speed image acquisition system during deformation and failure of HSR specimen are also included.

PURPOSE. This study was to evaluate the effect of the solution temperature on the mechanical properties of dualcure resin cements. MATERIALS AND METHODS. For the study, five dual-cure resin cements were chosen and light cured. To evaluate the effect of temperature on the specimens, the light-cured specimens were immersed in deionized water at three different temperatures (4, 37 and 60℃) for 7 days. The control specimens were aged in a 37℃ dry and dark chamber for 24 hours. The mechanical properties of the light-cured specimens were evaluated using the Vickers hardness test, three-point bending test, and compression test, respectively. Both flexural and compressive properties were evaluated using a universal testing machine. The data were analyzed using a two way ANOVA with Tukey test to perform multiple comparisons (α=0.05). RESULTS. After immersion, the specimens showed significantly different microhardness, flexural, and compressive properties compared to the control case regardless of solution temperatures. Depending on the resin brand, the microhardness difference between the top and bottom surfaces ranged approximately 3.3-12.2%. Among the specimens, BisCem and Calibra showed the highest and lowest decrease of flexural strength, respectively. Also, Calibra and Multilink Automix showed the highest and lowest decrease of compressive strength, respectively compared to the control case. CONCLUSION. The examined dual-cure resin cements had compatible flexural and compressive properties with most methacrylate-based composite resins and the underlying dentin regardless of solution temperature. However, the effect of the solution temperature on the mechanical properties was not consistent and depended more on the resin brand. [J Adv Prosthodont 2013;5:133-9]

Balsa wood is an appropriate core material for structural sandwich applications due to its high strength- and stiffness-to-weight ratios. However, the mechanical properties vary considerably owing to the inherent scattering of natural wood materials. One approach to reduce this scatter and tailor the mechanical properties according to specific application needs is to recompose the natural material into a veneered material consisting of veneer layers of different grain orientations, which are adhesively bonded together. The mechanical properties of such a veneered balsa wood, composed of alternating 0°/90° grain orientations, were investigated at ambient temperature according to corresponding standards. The properties were significantly influenced by the orthotropy on the material scale within one veneer layer and on the system scale within the assembled veneer layers. Standardized experimental set-ups and specimen geometries may produce artifacts such as buckling or strain hardening which deviate from the material behavior in real structures. The thin adhesive between the veneer layers did not negatively affect the mechanical behavior since failure occurred within the veneer layers and not in the interfaces.

Powder-epoxy resins have been shown to possess desirable properties making them suitable as a matrix for the production of composite wind blades. CFRP laminates manufactured using a powder-epoxy matrix were tested to determine mechanical properties. The laminates were manufactured using a noncrimp stitched unidirectional fabric and were compared to laminates manufactured from fibre tows with tension applied during the curing cycle. The tensioned case was investigated as a benchmark for superior fibre straightness mimicking the pultrusion process whereas the fabric was representative of materials used in industry. The materials were mechanically tested in the longitudinal and transverse directions in both tension and compression to determine strength and modulus. Results showed that the stitched case had a normalised tensile strength notably less than the tensioned tows in the longitudinal and transverse directions. While there was less of a drop in compressive properties in the longitudinal direction, the strength of the stitched case in the transverse direction was approximately 7% greater. No significant drop in modulus was observed due to stitching. It can be concluded that non-crimp carbon fabrics with powder epoxy matrices offer exceptional stiffness properties making them a suitable candidate for the production of spar caps in wind blades

The tensile, compressive and shear behavior of standardized specimens cut from a veneered balsa wood used as structural sandwich core was investigated at ambient temperatures of up to 250 degrees C. The average moisture content was 9.1%. The specimens' responses were strongly affected by the configuration of the veneer layers. Specimens with a higher number of 0 degrees veneer layers in the loading direction exhibited higher strength and stiffness at each temperature. Independent of the loading type, the specimens gradually lost strength and stiffness up to the wood-burning temperature of 250 degrees C due to the softening of the hemicellulose and lignin. Smaller cross sections with more surfaces cut perpendicular to the grain dried faster and thus delayed the degradation of properties. The dominant failure modes did not change with increasing temperature if the behavior remained either fiber- or matrix-dominated. The failure mode changed if the behavior shifted from fiber-dominated at lower temperatures to matrix-dominated at higher temperatures. The degradation of the properties of the adhesive between the veneer layers affected specimen behavior only at the highest temperature. (C) 2019 The Authors. Published by Elsevier Ltd.