Evaluation Of Mechanical Properties Research Articles

Fabrication of Cu/Al–Al2O3 laminar composites using squeeze casting and roll bonding techniques: Evaluation of microstructure, mechanical properties and wear characteristics

The influence of Al2O3 whiskers addition on the microstructure, tensile, hardness, and wear characteristics of Cu/Al–Al2O3 composites were examined. The squeeze casting was used to fabricate Al–Al2O3 composites with different volume fractions of whiskers. Then, they were bonded to Cu layers. The microstructural and morphological examination were carried out by using SEM, XRD, and EBSD analyses. For the as-cast composites, the agglomeration of whiskers was observed which was then decreased by the following roll bonding process. For the roll bonded composites, the tensile strengths of composites were 210 MPa, 233 MPa, and 250 MPa For Cu/Al-(5 % vol) Al2O3, Cu/Al-(15 % vol) Al2O3, and Cu/Al-(25 % vol) Al2O3, respectively. The wear rate decreased versus volume fraction of whiskers which is correlated with the enhanced hardness of layers in composites. Less material loss and less debris were observed in composites with a higher volume fraction of whiskers.

Evaluation of Residual Mechanical Properties of Non-sintered Hwangto Concrete Exposed to High Temperatures Using Ultrasonic Pulse Velocity Method

Evaluation of Residual Mechanical Properties of Non-sintered Hwangto Concrete Exposed to High Temperatures Using Ultrasonic Pulse Velocity Method

Evaluation of Mechanical Properties of AISI 4330 Steel under Martempering Heat Treatment

Evaluation of Mechanical Properties of AISI 4330 Steel under Martempering Heat Treatment

Evaluation of Mechanical Properties of Self-cured, Heat-cured, and Photosensitive 3D Printing Resins After the Addition of Silica Nanoparticles

This study evaluated investigate the addition of silica nanoparticles in autopolymerizable resin and into liquid resin for 3D printing and compare them with CAD-CAM blocks and thermopolymerizable resin, regarding flexural strength and surface roughness. Eight groups (n=12) were created according to the types of materials: autopolymerizable resin (G1-G4), photosensitive resin for 3D printing (G5-G6), PMMA block (G7) and thermopolymerizable resin (G8). Functionalized silica nanoparticles (0.5-1.5 wt%) were added in groups G2-G4 and G6. Mechanical flexural strength, surface roughness and morphological analysis were carried out to evaluate the properties of the samples. One-way ANOVA, followed by Tukey's post-hoc test, was used to evaluate the data. The average surface roughness was higher in group G7 and lower in the G8 group, with a statistical difference (p < 0.001). The G8 and G1-G4 showed no significant difference in surface roughness. The G5 and G6 presented surface roughness higher than that recommended by Borchers and Bollen (Ra=0.2 µm). The incorporation of nanoparticles into self-polymerizing acrylic resins negatively affected the mechanical properties of the material, reducing flexural strength. The G5 and G6 demonstrated the lowest flexural strength (p<0.001), presenting values lower than those recommended by ISO (σ >60 MPa) regardless of the incorporation or not of silica nanoparticles. The G7 presented the highest flexural strength value followed by the G8. Within the limits of this study, it may be concluded that the addition of silica nanoparticles did not improve the flexural strength the G6 and also affected negatively the mechanical properties of self-polymerizing acrylic resins.

Evaluation of Thermal and Mechanical Properties of Foamed Phosphogypsum-Based Cementitious Materials for Well Cementing in Hydrate Reservoirs

As detrimental byproduct waste generated during the production of fertilizers, phosphogypsum can be harmlessly treated by producing phosphogypsum-based cementitious materials (PGCs) for offshore well cementing in hydrate reservoirs. To be specific, the excellent mechanical properties of PGCs significantly promote wellbore stability. And the preeminent temperature control performance of PGCs helps to control undesirable gas channeling, increasing the formation stability of natural gas hydrate (NGH) reservoirs. Notably, to further enhance temperature control performance, foaming agents are added to PGCs to increase porosity, which however reduces the compressive strength and increases the risk of wellbore instability. Therefore, the synergetic effect between temperature control performance and mechanical properties should be quantitatively evaluated to enhance the overall performance of foamed PGCs for well cementing in NGH reservoirs. But so far, most existing studies of foamed PGCs are limited to experimental work and ignore the synergetic effect. Motivated by this, we combine experimental work with theoretical work to investigate the correlations between the porosity, temperature control performance, and mechanical properties of foamed PGCs. Specifically, the thermal conductivity and compressive strength of foamed PGCs are accurately determined through experimental measurements, then theoretical models are proposed to make up for the non-repeatability of experiments. The results show that, when the porosity increases from 6% to 70%, the 7 d and 28 d compressive strengths of foamed PGCs respectively decrease from 21.3 MPa to 0.9 MPa and from 23.5 MPa to 1.0 MPa, and the thermal conductivity decreases from 0.33 W·m−1·K−1 to 0.12 W·m−1·K−1. Additionally, an overall performance index evaluation system is established, advancing the application of foamed PGCs for well cementing in NGH reservoirs and promoting the recycling of phosphogypsum.

Microstructural Evolution and Wear Resistance of Surface Alloyed AISI 316L Stainless Steel with Equi-atomic CoCrFeMnTi by Continuous Wave Diode Laser

In this investigation, a multicomponent alloyed surface was developed on AISI 316L stainless steel (AISI 316L SS) substrate by melting it with a fiber coupled diode laser having 3.6 mm beam diameter (using argon as shrouding gas) along with simultaneous melting of equiatomic pre-mixed elemental powders of cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn) and titanium (Ti) (high entropy alloy). The process parameters used in the experiment were laser power (1800–2200 W) and scan speed (6 mm/sec to 8 mm/sec). Following laser surface alloying (LSA) a detailed microstructural characterization of the surface and evaluation of surface mechanical properties (micro/nano hardness, Young’s modulus and wear resistance) were undertaken. Due to LSA there is formation of near eutectic microstructure consisting of FCC and BCC phase mixtures along with the precipitates of Fe2Ti randomly distributed in the microstructure which was confirmed by X-ray diffraction (XRD) and electron back scattered diffraction (EBSD) analysis. There is an increase in microhardness in the processed zone from 180 VHN (of as received AISI 316L SS) to 309–650 VHN. In addition, there is an increase in Young’s modulus from 208 GPa for as received AISI 316L SS to 228–301 GPa for laser surface alloyed zone. The wear resistance (against WC ball in fretting wear mode) property of AISI 316L SS substrate after LSA was superior to the substrate. The wear mechanism was established.

Evaluation of mechanical properties and potential environmental applications of biomimetic mineralized composites

With the growing emphasis on environmental protection, there has been extensive research on new green cementitious materials suitable for different conditions. This study focuses on the influence of key environmental factors on proposed biomimetic mineralized composites (BMC) using polyacrylic acid (PAA) as a modifier, based on the biomimetic chemistry induced carbonate precipitation (BCICP) method. The environmental factors examined include the cementing matrices type, the magnesium ions concentration, and the cementing solution pH. The samples treated under various conditions were evaluated for their unconfined compressive strength (UCS) and calcium carbonate content, and their microstructure was characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results demonstrate that the BMC treatment could achieve high-strength cementation for both Toyoura sand and Fujian quartz sand, with a more pronounced enhancement observed for Toyoura sand. Magnesium ions reduce the cementation effect, and they cannot fully replace calcium ions in participating in the cementation process. Moreover, the cementing solution pH significantly influences the cementation effect, with the best acid-base condition for PAA to modify BMC sand samples found at a pH of 11.5. Overall, the BMC exhibits high performance under various environmental conditions. These findings could provide valuable insights into the influence of environmental factors and the potential applications of BMC in diverse environments.

Evaluation of Major Physical and Mechanical Properties of Trembling Aspen Lumber.

Trembling aspen (Populus tremuloides) is one of the major species within Populus, a predominant genus of hardwoods in North America. However, its utilization has been limited to pulp and paper or wood-based composite boards. This study aimed at evaluating the major physical and mechanical properties of trembling aspen lumber, with an ultimate objective of using this species to produce engineered wood products (EWPs). The testing materials consisted of 2 × 4 (38 mm × 89 mm) trembling aspen lumber pieces in lengths of 8, 10, and 12 feet (2.44, 3.05, and 3.66 m) with two visual grades, select structural (SS) and No. 2. Machine Stress-Rated (MSR), and longitudinal stress wave (LSW), edgewise third-point bending (EWB), and axial tension tests were conducted on the lumber. It was found that, (1) by increasing the maximum knot size by a half-inch from one-quarter inch, the minimum modulus of elasticity (MOE) measured using the MSR, the mean, and the fifth-percentile ultimate tensile strength (UTS) decreased by about 8.8%, 20.1%, and 29.8%, respectively. (2) Approximately 44% of the trembling aspen lumber met the 1450f-1.3E grade for MSR lumber, and 62% qualified for the 1200f-1.2E grade. (3) There was a great potential for manufacturing cross-laminated timber (CLT) of grade E3, with a rejection rate of about 29%. (4) The mean UTS and MOE values of the SS-grade trembling aspen lumber were 22.88 MPa and 9519 MPa, respectively, being 25.5% and 11.3% lower than that of Spruce-Pine-Fir (S-P-F) lumber. The fifth-percentile UTS and MOE values were 11.57 MPa and 7404 MPa, respectively, marking a decrease of 13.3% and 1.5% compared to the S-P-F lumber. (5) The oven-dried specific gravity (SG) of the trembling aspen wood was 0.40, which was about 3.5% larger than the value provided in the Wood Handbook.

Probabilistic analysis of homogenized elastic property for resin products fabricated by additive manufacturing based on three-dimensional random field modeling of microstructure

Additive manufacturing (AM) techniques have been used in several fields of science and industry, and fabrication techniques are being updated. For this fact, especially, for industrial use, mechanical property evaluation methodologies for AM products and standards for product quality assessment should also be well established. In this paper, a probabilistic evaluation of the homogenized elastic properties of a resin product fabricated by a material extrusion-based AM technique is attempted by considering the randomness of both material and microscopic geometrical quantities. This AM method fabricates a resin structure by piling up melted resin, and to decrease consumed material and influence of thermal deformation, the inner structure of the fabricated products will include many pores and its geometry is difficult to be well controlled. From this fact, the products will be regarded as a heterogeneous material with complex random microstructure. This will cause difficulty in the evaluation of its apparent material properties and therefore a probabilistic homogenization analysis is attempted for their quantitative estimation in this study. In particular, to investigate probabilistic properties of microscopic geometry, a random field modeling technique is employed for the evaluation of autocorrelation of the microscopic geometrical parameter, and the results of the autocorrelation identified by experimental observation are introduced to the probabilistic homogenization analysis. The two-dimensional or three-dimensional random field modeling is attempted, and the effectiveness of this approach is investigated by comparing it with the experimental result.

Investigation of an Increased Particle Size Distribution of Ti-6Al-4V Powders Used for Laser-Based Powder Bed Fusion of Metals.

This study investigates the potential benefits of integrating coarser particle size distributions (PSDs) of 45-106 µm into laser-based powder bed fusion of metals (PBF-LB/M), aiming to reduce costs while maintaining quality standards. Despite the considerable advantages of PBF-LB/M for producing intricate geometries with high precision, the high cost of metal powders remains a barrier to its widespread adoption. By exploring the use of coarser PSDs, particularly from electron beam-based powder bed fusion of metals (PBF-EB/M), significant cost-saving opportunities are identified. Through a comprehensive powder characterization, process analysis, and mechanical property evaluation, this study demonstrates that PBF-LB/M can effectively utilize coarser powders while achieving comparable mechanical properties as those produced with a 20-53 µm PSD. Adaptations to the process parameters enable the successful processing of coarser powders, maintaining high relative density components with minimal porosity. Additionally, market surveys reveal substantial cost differentials between PBF-LB/M and PBF-EB/M powders, indicating a 40% cost reduction potential for the feedstock material by integrating coarser PSDs into PBF-LB/M. Overall, this study provides valuable insights into the economic and technical feasibility of printing with coarser powders in PBF-LB/M, offering promising avenues for cost reduction without compromising quality, thus enhancing competitiveness and the adoption of the technology in manufacturing applications.

Research on improving the frost resistance and self-repair performance of limestone calcined clay cement concrete by microcapsules

Limestone calcined clay cement (LC3) concrete has emerged as a pivotal construction material aimed at mitigating carbon emissions and bolstering sustainability. However, LC3 concrete confronts durability challenges in frigid regions attributable to freeze-thaw cycles. Microcapsule self-repair technology, as an innovative paradigm, presents a promising avenue to augment the freeze-thaw resistance and self-repair attributes of LC3 concrete. Within this inquiry, microcapsules containing isophorone diisocyanate (IPDI) and encapsulated with microcrystalline wax, ceresine wax, and CaCO3 were synthesized and effectively integrated into LC3 concrete matrices. Freeze-thaw cycle investigations were conducted to juxtapose LC3 concrete specimens with and without microcapsules. The findings evinced that LC3 concrete augmented with microcapsules demonstrated enhanced resistance to freeze-thaw cycles, thereby mitigating mass loss and compressive strength degradation. Microscopic structural analyses, pore size distribution assessments, mechanical property evaluations, impermeability, and ultrasonic waveform analyses of LC3 concrete samples featuring microcapsules corroborated the heightened freeze-thaw resistance, thus fortifying its applicability in rigorous environments. Moreover, deliberate pre-cracking of the concrete surface unveiled the self-repair efficacy of microcapsules, with empirical observations underscoring the prompt crack remediation capabilities of the implemented technology.

Evaluation of mechanical properties of nanoparticle-coated orthodontic brackets and wires

Evaluation of mechanical properties of nanoparticle-coated orthodontic brackets and wires

Small punch evaluation of mechanical properties for 310S stainless steel considering pre-strain effect

Strain strengthening technology is widely used in practical engineering to increase the allowable stress of materials in pressure vessel manufacturing. Small punch analysis was performed using less material in this study to analyse the influence of pre-strain on the mechanical properties of 310S stainless steel. The results indicated that the material yield strength and ultimate tensile strength increased with pre-strain deformation. Similarly, the small punch characteristic parameters increased owing to the influence of the pre-strain, proving that the small punch test could estimate the evolution of mechanical properties along with pre-strain deformation. Small punch characteristic parameters at different deformation stages were analysed. In addition to the maximum load, small punch parameters at the inflection point were used in the ultimate tensile strength estimation. The small punch deformation features and stress distribution were discussed based on numerical simulations. Finally, an ultimate tensile strength estimation method based on membrane stretching model was proposed. Additionally, the strain hardening parameters considering the effect of pre-strain deformation were discussed.

Structure and mechanical properties of a refractory Al7.5(NbTiZr)92.5 medium-entropy alloy subjected to long-term annealing and oxidation

Recently, Al-containing refractory high/medium-entropy alloys (RH/MEAs) have attracted special attention from materials scientists worldwide. Some of these alloys demonstrated an excellent combination of high-temperature strength and room-temperature tensile ductility provided by the formation of a structure consisting of body-centred cubic (bcc) matrix and B2 nanodomains/particles. However, oxidation resistance and phase stability, and, more importantly, the resulting mechanical properties of the Al-containing RH/MEAs, which are critical characteristics for high-temperature structural materials, remain unexplored. Herein, these aspects were extensively investigated for the Al7.5(NbTiZr)92.5 (in at%) alloy having an initial bcc + B2 structure. The alloy was subjected to long-term (500 h) annealing or oxidation tests at 600, 700, and 800 °C followed by the evaluation of mechanical properties during uniaxial tension at 22 and 600 °C. Microstructural studies of the specimens exposed to long-term annealing showed the formation of Zr5Al3 particles that precipitated along the grain boundaries and within grain interiors. The volume fraction of these particles was the highest (∼16 %) after annealing at 600 °C and the lowest (∼0.5 %) after annealing at 800 °C. Oxidation tests revealed that the alloy was prone to pesting phenomena, which intensified with the temperature. The alloy could sustain pesting only up to 10 h at 600 °C, while it experienced a complete disintegration into powder after 5 h at 800 °C. The poor oxidation resistance originated from the formation of volumetric, non-protective (Al,Nb,Ti,Zr)O4 oxide. While insignificantly affecting the strength, long-term annealing or oxidation deteriorated the ductility of the Al7.5(NbTiZr)92.5 alloy both at 22 and 600 °C. The Zr5Al3 phase embrittled the alloy after long-term annealing at 600 or 700 °C, but marginally reduced the ductility in the 800°C-annealed specimens due to the low volume fraction and relatively homogeneous distribution of this phase. The oxidation for 1 h decreased the room-temperature ductility owing to the premature macroscopic localisation of plastic deformation induced by synergistic effects from the volumetric (Al,Nb,Ti,Zr)O4 oxide. This study highlights the necessity for the examination of a set of properties of promising RH/MEAs to critically assess perspectives of these alloys to find applications as new high-temperature materials in aircraft and aerospace sectors.

Experimental Evaluation of Mechanical Compression Properties of Aluminum Alloy Lattice Trusses for Anti-Ice System Applications

Experimental Evaluation of Mechanical Compression Properties of Aluminum Alloy Lattice Trusses for Anti-Ice System Applications

Biocomposite Films of Amylose Reinforced with Polylactic Acid by Solvent Casting Method Using a Pickering Emulsion Approach

Binary and ternary blends of amylose (AM), polylactic acid (PLA), and glycerol were prepared using a Pickering emulsion approach. Various formulations of AM/PLA with low PLA contents ranging from 3% to 12% were mixed with AM matrix and reinforced with 25% cellulose nanofibers (CNF), and PLA-grafted cellulose nanofibers (g-CNF), the latter to enhance miscibility. Polymeric films were fabricated through solvent casting and characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Wide-Angle X-ray Scattering (WAXS), and the evaluations of physical, mechanical properties, and wettability were performed using contact angle measurements. The binary blends of AM and PLA produced films suitable for packaging, pharmaceutical, or biomedical applications with excellent water barrier properties. The ternary blends of AM/CNF/PLA and AM/g-CNF/PLA nanocomposite films demonstrated enhanced tensile strength and reduced water permeability compared to AM/PLA films. Adding g-CNF resulted in better homogeneity and increased relative crystallinity from 33% to 35% compared to unmodified CNF. The application of Pickering emulsion in creating AM-based CNF/ PLA composites resulted in a notable enhancement in tensile strength by 47%. This study presents an effective approach for producing biodegradable and reinforced PLA-based nanocomposite films, which show promise as bio-nanocomposite materials for food packaging applications.

Towards sustainable composites: Evaluation of mechanical properties, erosion behavior and applications of natural fiber-epoxy composites

Sustainable production and consumption, carried to materials and engineering applications, translates to a need for recyclable, reusable, and/or biodegradable materials. With its lower cost, lighter weight, and less carbon footprint compared to traditional glass and carbon fiber composites, natural fiber-reinforced composites are drawing more attention from the scientific community and the industrial sector. The natural fiber’s high variability and relatively inferior mechanical properties necessitate comprehensive characterization for accurate evaluation of their properties and fitness for different applications. In this research, various locally grown natural fibers (Flax, Jute, and Luffa) were sourced, characterized, and used to synthesize natural fiber-reinforced epoxy composites. The tensile, flexural, impact properties, and erosion resistance of the composites was evaluated. Compared to the other natural fiber composites, the Jute-Epoxy composite achieved the highest tensile strength and tensile modulus with 31 MPa and 4.8 GPa respectively; Jute-Epoxy also achieved the highest flexural strength and flexural modulus, with and 60 MPa and 2.4 GPa respectively. This superior mechanical performance is due to the relatively high strength of the Jute fiber and its high adhesion to the matrix, which is supported by fractographic evidence. Luffa-Epoxy composites in general had the lowest properties of all the tested materials. The erosion test results showed that the Jute-Epoxy composites had the highest erosion resistance of all the tested materials; with 30% more erosion resistance compared to glass-fiber epoxy composites. Based on the experimental results of the investigation and similar previous research, the current and potential applications of natural fiber composites were discussed.

Mechanical Properties Evaluation Based on the Variable Gradient of Body-Centered-Cubic-Based Lattice Structure Prepared by Laser Powder Bed Fusion

Mechanical Properties Evaluation Based on the Variable Gradient of Body-Centered-Cubic-Based Lattice Structure Prepared by Laser Powder Bed Fusion

Wet-Spinning Preparation of High-Performance Phenol-Modified Melamine-Formaldehyde Fibers

In order to improve the toughness of melamine formaldehyde (MF) fibers, the modified fibers with varying synthesis mole ratios were fabricated through wet spinning utilizing melamine and paraformaldehyde as the primary constituents and phenol as the modifying agent. The structural characteristics and properties of the fibers were assessed and examined through Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and mechanical property evaluations. The results showed that the incorporation of phenol led to a significant enhancement in both the thermal stability and mechanical properties of the fibers. Specifically, when the mole ratio of melamine, phenol, and paraformaldehyde was 1:1:4 and the heat curing temperature was 180 °C, the fiber exhibited a breaking strength of 151 MPa and an elongation at break of 15.1%. This represented an increase in elongation at break of approximately 84% compared to the unmodified fiber without phenol. Furthermore, the thermal properties of the modified fibers were notably improved, as evidenced by an increase in char yield at 700 °C from 27.7% to 62.5%.

Evaluation of mechanical, morphological, and dynamic mechanical properties on basalt/E-glass fiber/epoxy modified with MWCNTs + SiO2 hybrid nanocomposites

Evaluation of mechanical, morphological, and dynamic mechanical properties on basalt/E-glass fiber/epoxy modified with MWCNTs + SiO2 hybrid nanocomposites