Improvement In Tensile Properties Research Articles

Development and Characterization of Hybrid Particulate-fiber Reinforced Epoxy Composites

Although considered wastes, animal fibers and gastropod shell particles are biodegradable, have low density, high stiffness, considerably high impact absorption capacity and relatively low cost. Therefore, they are finding increasing use as reinforcement materials in polymer composites. This research work studied the tensile, hardness, and wear resistance properties of hybrid snail shell (SSP) and chicken feather barb fibers (CFB) reinforced epoxy composites. The stir cast molding technique was utilized to synthesize the composite samples with 3, 6, 9, 12, 15, and 18 wt.% of the hybrid SSPs/CFB. Compared with the control samples, SSP/CFB hybrid reinforcements enhanced the mechanical properties of the composites. Composites with intermediate weight fraction of 9 wt.% SSP/CFB exhibited overall optimum properties when benchmarked against the control sample with approximately 37, 37, 133, 19, and 59% improvement in wear, hardness, impact, and ultimate tensile strength properties respectively. These enhancements suggested a synergistic effect of the two reinforcement phases. The results presented in this study demonstrated the potential of utilizing bio-derived waste materials for synthesizing eco-friendly composites.

The influence of graphene nanoplatelet content on the mechanical properties and microstructure of sustainable concrete

The effects of the content of graphene nanoplatelets (GNPs) on the mechanical properties and microstructure of sustainable concrete were investigated. Aqueous solutions were prepared, using a wet-dispersion technique to disperse GNPs in the mixing water. Concrete batches were prepared using different GNP fractions (0.05, 0.1, 0.25, 0.5, 1 and 2% by weight of cement), and their compressive, flexural and tensile strengths were determined at 28 days. Qualitative microstructural analyses were performed using scanning electron microscopy and energy dispersive X-ray analysis. The results obtained were analysed using analysis of variance (Anova), which demonstrated improvements in all strength properties when using GNP filaments regardless of their weight fraction. The batch containing 0.5% GNPs showed the largest strength improvements, with improvements in compressive, flexural and tensile strength properties of 22.6%, 23.9% and 255.4%, respectively. Microstructural analysis showed a good dispersion of nanofilaments inside the concrete matrix through the dispersion technique used in this study. Finally, Anova revealed statistically significant relationships between the GNP content and the compressive, flexural and tensile strengths of the concrete specimens. The results highlight the importance of the GNP content in influencing the concrete's mechanical properties.

The synergy of the matrix modification and fiber geometry to enhance the thermo‐mechanical properties of basalt fiber‐polypropylene composites for automotive applications

AbstractBasalt fiber reinforced polypropylene composites with two initial fiber lengths (3.2 and 6.4 mm) were fabricated using twin‐screw extrusion compounding. In the case of composites with smaller initial fiber length, basalt fibers predominantly served as nucleating agents for polypropylene thereby resulting in an increase in the degree of crystallinity. The addition of polypropylene‐g‐maleic anhydride (PP‐g‐MA) caused the matrix to become amorphous, which was due to the establishment of a fiber–matrix interphase. This behavior was different for the composites with relatively larger initial fiber length especially at higher fiber content. The reduction in fiber length in the composites caused a decrease in crystallinity, as this hindered the ability of the polypropylene matrix to form crystals. Addition of PP‐g‐MA established a fiber–matrix interphase thereby synergistically contributing to the increased matrix amorphousness of the basalt fiber reinforced polypropylene composites with 6.4 mm initial fiber length. Reduced fiber length due to processing also accelerated the thermal degradation of the composites with an initial fiber length of 6.4 mm. However, the reduction in fiber length due to processing resulted in increased fiber orientation, which contributed to the improvement in tensile and flexural properties of the basalt fiber reinforced polypropylene composites with an initial fiber length of 6.4 mm. At 30% fiber content, the tensile strength and modulus of basalt fiber reinforced matrix modified polypropylene composites with 6.4 mm initial fiber length improved by 18% and 13% as compared with the composites with 3.2 mm initial fiber length.

Ink-Based Additive Manufacturing of a Polymer/Coal Composite: A Non-Traditional Reinforcement.

Coal, a crucial natural resource traditionally employed for generating carbon-rich materials and powering global industries, has faced escalating scrutiny due to its adverse environmental impacts outweighing its utility in the contemporary world. In response to the worldwide shift toward sustainability, the United States alone has witnessed an approximate 50% reduction in coal consumption. Nevertheless, the ample availability of coal has spurred interest in identifying alternative sustainable applications. This research delves into the feasibility of utilizing coal as a nonconventional carbon-rich reinforcement in direct ink writing (DIW)-based 3D printing techniques. Our investigation here involves a thermosetting resin serving as a matrix, incorporating pulverized coal (250 μm in size) and carbon black as the reinforcement and a viscosity modifier, respectively. The ink formulation is meticulously designed to exhibit shear-thinning behavior essential for DIW 3D printing, ensuring uniform and continuous printing. Mechanical properties are assessed through the 3D printing of ASTM standard specimens to validate the reinforcing impact. Remarkably, the study reveals that a 2 wt % coal concentration in the ink leads to a substantial improvement in both tensile and flexural properties, resulting in enhancements of 35 and 12.5%, respectively. Additionally, the research demonstrates the printability of various geometries with coal as reinforcement, opening up new possibilities for coal utilization while pursuing more sustainable manufacturing and applications.

Improved creep strength of 10% Cr steels with low N and high B content via increasing quenching temperature

An increase in quenching temperature from 1050 °C to 1100 °C is found to be an effective approach to improving the creep strength at 650 °C in two Re-containing 10% Cr martensitic steels with low N and high B contents. Creep time at creep tests of 650 °C/120 MPa increases at the expense of the appearance of the steady-state creep stage in both steels. Moreover, the room yield strength and ultimate tensile strength are also increased by 10% with increasing quenching temperature in the steel with 0.8% Cu, whereas tensile tests at 650 °C do not reveal the increment in strength in both steels. Improvement in creep and tensile properties is caused by an increase in particle strengthening due to M23C6 carbides, mainly in both steels. The NbX, VX, and “Cu”-clusters/precipitates make minor contributions to the change in particle strengthening. Refinement of M23C6 carbides in both steels is accompanied by an increase in particle number density along the martensitic laths and an increase in the fraction of fine particles with sizes below 50 nm. Such changes in M23C6 carbide dispersions are caused by an increase in the lath area per unit volume and the enrichment of the solid solution with boron because of the dissolution of W2B particles with increasing quenching temperatures.

Effect of abnormal grain refinement on synchronous strengthening behavior of Fe50Mn30Co10Cr10 high entropy alloys

Improving processing efficiency while obtaining excellent material formation and mechanical properties is the primary concern of the manufacturing industry. This study aims to refine the grains of Fe50Mn30Co10Cr10 high entropy alloy during friction stir processing, achieving exceptional tensile properties in the stir zone by increasing the rotational speed. The key driver behind grain refinement lies in the alloy's inherently low stacking fault energy, with the primary recrystallization mechanism being discontinuous dynamic recrystallization. The freshly recrystallized fine grains share analogous microstructures and energy levels during severe plastic deformation, which engenders a state of increased competition among them. This robust competitive dynamic impedes grain growth, thereby promoting the development of refined grains. This microstructure proves instrumental in avoiding premature microcracking during tensile loading by hindering martensite formation, consequently improving the UTS and EL of the material. Nevertheless, the high heat input and substantial strain result in an increase of temperature and strain energy in the system, eventually disrupting the high energy system and causing grain coarsening as the rotational speed continues to increase. This coarsened grain and high martensite fraction lead to premature initiation of cracks under tensile loading, which is not conducive to further improvement of tensile properties.

Tailoring the Microstructure using Quenching and Partitioning Processing in a Commercial Mn-Si-Cr Spring Steel to Improve Tensile Properties

AbstractThis study explores a novel approach to quenching and partitioning (Q&P) heat treatment applied to AISI 9260 spring steel, comprising Fe-0.65C-1.58Mn-1.05Si-0.41Cr (wt.%). Our research focuses on balancing strength and ductility through optimized Q&P pathways, leading to a diverse microstructure that includes martensite, bainite, carbide, and retained austenite. Advanced X-ray diffraction and scanning electron microscopy techniques were employed to analyze the complexities of this microstructure. A key aspect of this study is the precise control of partitioning temperature and time, crucial for modulating lattice distortion and dislocation density within martensitic and bainitic structures. Optimal partitioning temperature promotes carbon distribution into austenite, tempering lattice distortions, and dislocation densities. Concurrently, carbide precipitation and segregation contribute to the refinement of the bainite phase. The sample quenched at 125 °C and partitioned at 350 °C (Q&P-125/350) demonstrates notable mechanical properties: a yield strength of 950 ± 15 MPa, an ultimate tensile strength of 1710 ± 15 MPa, and an elongation of approximately 9.7%. These results are partly attributed to the effect of silicon in preventing cementite coarsening and the effective distribution of carbide. Our findings highlight the potential of Q&P heat treatment in developing tailored microstructures with enhanced mechanical properties in steel, without relying on costly alloying elements. This approach presents new avenues for the design and application of high-performance materials.

Improving M30 Concrete Performance with Recron 3S Fiber and Steel Slag: A Systematic Review

Abstract: This literature review delves into the potential for enhancing the performance of M30-grade concrete through the incorporation of Recron 3S fiber and steel slag aggregate to address sustainability issues in the construction industry. By systematically analyzing existing research, the review assesses the mechanical properties and sustainability implications of these substitutions. Recron 3S fibres offer improvements in tensile and flexural properties, reducing crack propagation and increasing ductility. In contrast, steel slag aggregate enhances compressive strength, durability, and resistance to alkali-silica reactions, all while utilizing recycled materials.

Improving Tensile Properties of Dissimilar TLP Bonding Joints of IN718 Nickel-Based Superalloy/316LN Austenitic Steel by Long-Term Post-bonded Homogenization Treatment

Improving Tensile Properties of Dissimilar TLP Bonding Joints of IN718 Nickel-Based Superalloy/316LN Austenitic Steel by Long-Term Post-bonded Homogenization Treatment

Understanding the filling effect of ice on the mechanical properties of calcium silicate hydrate gel

Ice exhibits good mechanical performance at low temperatures, and when it replaces the weakest pores in cement-based materials, it can noticeably enhance the overall mechanical properties of the material. However, the specific micro-mechanisms that contribute to the improvement of tensile mechanical properties in gel pores at low temperatures are still not fully understood. Based on the results of molecular dynamics simulations, significant roles have been attributed to pore size and temperature in the mechanical performance of gel pores at low temperatures. A thorough investigation was conducted on the process of tensile failure in saturated gel pores, as well as the changes in bonding interactions between calcium silicate hydrate (CSH)-ice and the unfrozen water film (UWF) at different pore sizes and temperatures. The results indicate that increasing pore size and decreasing temperature can improve the mechanical properties of saturated gel pores. With the decrease in temperature, the mechanical properties of the three gel pore systems with heights of 100 Å, 68 Å, and 54 Å were significantly enhanced. Under an engineering strain rate of 8×10−4/ps, the tensile strength and elastic modulus of gel pores increased from 0.57 GPa and 17.81 GPa at 250 K, to 0.97 GPa and 20.87 GPa at 150 K, respectively. To explain this phenomenon, further studies were conducted on the radial distribution function and dynamic hydrogen bonding behavior. The critical contribution of the hydrogen bond network to the mechanical performance of gel pores was discovered. The hydrogen bond structure which experienced the earliest damage, was investigated. As the strain increased, the hydrogen bonds continuously broke and reformed. This research provides a theoretical understanding of the mechanical properties of gel pores under low-temperature conditions.

Improvement of microstructures and mechanical properties of Mg–3Zn-0.5Zr by friction stir processing

Friction stir processing (FSP) has been applied to improve the microstructure and tensile performance of as-cast Mg–3Zn-0.5Zr magnesium alloy. By FSP, grains within the stir zone (SZ) demonstrate noticeable refinement and the varied processing parameters can lead to the formation of both strong and weak textures within the SZ. Second-phase particles are broken down, dispersed, and partially re-dissolved. In addition, optimal processing parameters lead to enhanced uniformity in refined grains and increased dispersion of secondary-phase particles, resulting in improved both in microhardness and tensile properties. The sample processed at 800-200 (rpm/mm∙min−1) demonstrates an overall improvement in tensile properties compared to the base material, with yield strength, ultimate strength, and uniform elongation of 93.7 MPa, 215.0 MPa, and 25.4%, respectively.

Improvement of tensile properties through Nb addition and heat treatment in additively manufactured 316L stainless steel using directed energy deposition

Metal additive manufacturing (AM) has been applied in various fields because it allows the manufacture of parts with complex shapes. In this study, 316 L stainless steel specimens with 0 and 2 wt% Nb were fabricated using direct energy deposition, and heat treatment was performed at various temperatures. The addition of Nb changed the microstructure of the steel, including the grain size and Nb segregation. When heat treatment was performed, microstructural evolution of the cell boundary, dislocation density, and deformation twin density occurred. These microstructural changes improved the tensile properties of the heat-treated specimens containing Nb. The yield strength, tensile strength, and elongation of the specimens containing Nb with heat treatment at 800 °C were 530 MPa, 757 MPa, and 39%, respectively, which represent great improvements compared to specimens without Nb. These results show that the addition of Nb to 316 L stainless steel together with heat treatment at an appropriate temperature endow the additively manufactured stainless steel with excellent tensile properties.

Preliminary evaluation of properties and performance of natural rubber (NR) latex band for microplastic capturing in seawater

Microplastic particles are emerging water-laden waste that cause a worrying concern towards the environment and humans health. Due to its small size and geometry, and uncertain surface properties, the microplastic waste capturing method in water is still evolving. To date, a number of findings report on the emergence of microplastic surface charging, especially when exposed to water environment. In this study, the natural rubber (NR) latex band was utilized to capture the microplastic waste via a surface capturing mechanism. The NR band was produced using a film casting and curing methods. The surface charging mechanism on the NR band was introduced via the usage of high amount of ZDEC accelerator and, periodic stretching and relaxation procedures. In this work, ZDEC was used as an accelerator for the rubber formulation, and surface charge booster for the NR band. The surface charge of the NR band generates electrostatic interaction with the microplastic waste in water. The polypropylene (PP) microplastic was captured via the surface attraction mechanism using the manufactured NR band. Based on FTIR analysis, the presence of PP microplastic can be quantified on the contaminated NR band surface. The NR band shows the improvement in tensile and tear properties and crosslink density, mainly due to high amount of ZDEC used. At ZDEC loading of 20 phr, the NR band recorded the highest surface potential value, and this is owing to the formation of Zn2+ complex ions on its surface. XRF analysis indicates that the increment of Zn content in the NR band with increasing ZDEC content, that suggests the formation of Zn2+ complex ions.

Effect of rare Y-microalloyed Al–Mg filler materials on the microstructure and tensile properties of laser welded Al–Mg–Si alloys

The Al–Mg filler metals containing various amounts of yttrium (Y) were obtained and used to study the effect of the Y element on the microstructure and tensile properties of laser welded Al–Mg–Si alloys. The results revealed that compared with the unmodified welded joints, 0.1 wt%Y addition cannot effectively refine the grains. However, the 0.1 wt%Y addition effectively decreased the rich-Fe phases size and transformed the bulk β-AlFeMnSi phases into the fine granular AlFeMnSiY phases. Due to the precipitation strengthening, the welded joints with 0.1 wt%Y exhibited excellent mechanical properties, the highest tensile strength and elongation increased by 53.42 MPa and 5.58 %, respectively. As the Y content further increased, a significant grain refinement was observed in the weld zone. However, due to the small growth restriction factor of Y in aluminum alloys, the degree of grain refinement was limited. When 0.3 wt% Y was added, the grain size of the weld was the smallest, which was only reduced by 7.7 μm compared to the unmodified weld and similar to the weld with 0.5 wt%Y addition. Furthermore, the increase in solidification temperature range led to the growth of the second phase, as well as an increase in the number of coarse rich-Fe and Mg2Si phases. These combined reasons prevent further improvement of tensile properties of the welded joints.

Rapid Improvement of Fiber Tensile Properties via In Situ Biomimetic Robotic Pulling and Bayesian Optimization

For fiber technology, new approaches such as biomimetic materials, such as silks, are being intensively explored, providing new solutions for a variety of industries, including textiles, composites, and biomedical engineering. New approaches for spinning or these materials are needed. Despite recent advances in enhancing fiber tensile properties, achieving significant improvement in tensile properties remains a tedious and challenging task, suffering from little to no controlled extrusion process and difficult optimization in high‐dimensional parameter spaces. Herein, a novel robotic biomimetic pulling method that can rapidly enhance fiber tensile properties surpassing current methods in both speed and resulting fiber properties is shown. Using a controlled fiber‐pulling device with in situ tensile measurements and adaptive optimization based on Bayesian Optimization, fiber strength exceeding 300% of the traditional full factorial design method within just a few experimental iterations is reached. The rapid experimental method presents a potential avenue for enhancing the performance of artificial fibers across diverse industries and applications.

A high improvement of tensile properties and interfacial interaction of calcium silicate hydrate/hexagonal boron nitride layered nanostructures via defect field

Previous studies have shown that the increase in Young's modulus of cement-based materials by h-BN (about 20%) is lower than that of graphene and graphene oxide (an increase of 35.8%−78.6%). In order to further improve the interfacial interaction between calcium silicate hydrate (CSH) and hBN nanostructures, a series of defective hBN nanostructures were inserted between CSH layers to form defective hBN-CSH layered nanostructures. The interfacial interaction and tensile properties of hBN-CSH layered nanostructures were investigated, in considering the effect of internal (defect sizes in hBN) and external field (strain rate and temperature). The results show that the failure strain and stress of CSH models are enhanced by 18.18% and 14.74% with the incorporation of pure hBN while an increase of 35.53% and 31.58% in failure strain and stress is achieved by incorporating defective hBN (R3), attributed to high interfacial interaction. In addition, the tensile strain of defective hBN-CSH nanostructures (with a decrease of 33.49%) is more sensitive to temperature than that of free-defect hBN-CSH (with a decrease of 29.71%). Also, the tensile strain of defective hBN-CSH (R3) nanostructure (with an increase of 6.49%) is more sensitive to strain rate than that of free-defect hBN-CSH (with an increase of 4.38%). By constructing different interface interactions, a parameterized scheme is provided for the optimization and regulation of the spatial structure of the cement matrix.

Achieving ultra-tear resistant high-performance natural rubber nanocomposite via bio-inspired lignocellulosic compatibilization

Elastomers which are strong, tough, and resistant to tearing, are highly attractive for engineering applications such as conveyer belts, high-performance seals, tires, and soft robotics. Enhancing these properties for natural rubber materials is possible by utilizing nanoscale fillers, however the nanocomposite approach remains challenging because (a) nanofillers can impede latex molecular crosslinking, and (b) reduce the material’s inherent elasticity and compliance. This study demonstrates an approach to prepare ultra-strong, tear-resistant natural rubber nanocomposites using cellulose nanofibers decorated with nanoscale lignin. The reinforcement of latex with 0.1 wt% cellulose nanofibre compatibilized with 0.5 wt% lignin resulted in a 256% improvement in tear strength, 95% in tensile strength, and 50% in toughness, while retaining the elongation at break. Such a simultaneous improvement in tensile and tear properties has not been previously achieved through the latex casting method with any other fillers, and herein it is attributed to the nanoscale reinforcement efficiency of nanofibre coupled with enhanced interfacial adhesion between nanofibers and NR latex with the introduction of nanoscale lignin. This compatibilization approach has also resulted in improved resilience in the nanocomposites, as evidenced by the cycling loading and unloading analysis.

Evading the strength-ductility compromise in medium manganese steel by a novel low temperature warm rolling treatment

Strength-ductility trade-off is an enduring problem in a wide range of metals and alloys including the advanced high-strength steels. In this work, we propose a novel non-isothermal low-temperature warm rolling (WR) treatment which was applied after the conventional intercritical annealing (IA) in order to overcome the strength-ductility compromise in a medium manganese steel, Fe-5.1Mn-0.22C-0.85Si-0.42Al (composition in wt%). IA + WR treatment yielded a simultaneous improvement in tensile properties, wherein yield strength (YS), ultimate tensile strength (UTS), and ductility improved by 32%, 12%, and 6% respectively, compared to the conventional IA treatment. Despite an increase in the yield point elongation (2%) and Lüders strain (3%) in the IA + WR specimen, the ductility of the same improved as compared to the IA specimen. Microstructure of the IA + WR specimen was tailored by introducing a significantly higher dislocation density in the constituent ferrite and retained austenite (RA) phases along with a relatively higher density of planar defects (stacking faults and nano-twins) in the RA phase. X-ray line profile analysis quantified the increased dislocation density (order ∼1015 vs 1014 m−2) and twin fault probability (∼1.35% vs ∼0.12%) in the RA phase of the IA + WR compared to the IA specimen. The improvement in YS was primarily due to the increase in the dislocation density of the constituent phases in the IA + WR specimen. Introduction of a high density of lattice defects in the RA phase during the WR treatment above the Md30 temperature enhanced the mechanical stability of the RA phase, leading to a decreased rate of TRIP effect and formation of hierarchical twins during tensile deformation. The near-ubiquitous strength-ductility trade-off was overcome via a tailored microstructure consisting of regulated austenite stability leading to discontinuous TRIP effect, hierarchical twinning in RA phase, and favorable texture in the constituent phases. The present study provides a pathway to tailor the microstructure for escaping the strength-ductility paradox in different metastable FCC alloys such as stainless steel, HEAs, TWIP steels etc.

Effect of citric acid on thermal, phase morphological, and mechanical properties of poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide)/thermoplastic starch blends

Abstract This work investigated the thermal, morphological, and tensile properties of poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide) (PLLA-PEG-PLLA)/thermoplastic starch (TPS) blends with 3 wt% citric acid (CA) treatment of TPS. The blends with PLLA-PEG-PLLA/CA-TPS ratios of 100/0, 90/10, 80/20, and 60/40 (w/w) were investigated and compared with PLLA-PEG-PLLA/CA-free TPS blends. Crystallizability of the blends decreased and thermal stability increased as the TPS content increased. The thermal stability of the blends was found to improve after CA treatment of TPS. The PLLA-PEG-PLLA/CA-TPS blends showed better phase compatibility than those of the PLLA-PEG-PLLA/CA-free TPS blends. The tensile properties of the blends were improved by CA treatment of TPS. In conclusion, improvement in thermal stability, phase compatibility, and tensile properties of the PLLA-PEG-PLLA/TPS blends was obtained by CA treatment of TPS. The resulting PLLA-PEG-PLLA/CA-TPS blends could potentially be used to prepare biodegradable and flexible bioplastics.

Mechanical Properties Evaluation of Magnesium-Based Alloy Used for Dental Implant Synthesis

Background: Mg as well as its alloys are differing from other biomaterials through providing compatible physical and mechanical characteristics to the human bones. Also, their elastic modulus and densities were somewhat close to one another and thus removing elastic mismatches between the bone and implants. Furthermore, the Mg present naturally in bone structure, and it is essential metal for metabolism. Some mechanical properties (Hardness, diametral tensile) and corrosion resistance of enforced Mg by Strontium and alloyed with another biocompatible elements (Zn, Mn) were examined. Materials and methods: 135 samples were prepared for microhardness, diametral tensile, and corrosion test, divided to two groups 1st one pure Mg as a control group, 2nd group Mg alloy with different concentration of alloying elements to select the optimum ratio for alloying elements which consist of Zinc, Manganese, and Strontium). Result: Alloying of Mg with Zn, Mn and Sr, shows improvement in mechanical properties but dropping in corrosion resistance when compared with pure Mg. Conclusions: Alloying of pure Mg by ternary Zn, Mn and Sr have a valuable improvement in mechanical micro hardness and diametral tensile properties, but increases corrosion rate in comparison with pure Mg due to the effect of galvanic corrosion