Evaluation Of Tensile Properties Research Articles

Effect of cold rolling route and annealing on the microstructure and mechanical properties of AISI 316 L stainless steel

Since cross rolling promotes the transformation of austenite to deformation-induced α΄-martensite and increases the dislocation density in the retained austenite, the reversion/recrystallization annealing after cross rolling might be more effective to achieve finer grain sizes in metastable austenitic stainless steels. Accordingly, the effect of cold rolling route and annealing for grain refinement and improvement of mechanical properties of AISI 316 L stainless steel was systematically investigated in the present work. It was found and formulated that by increasing strain, the grain refinement efficiency during annealing is improved, the effect being more pronounced if the cold rolling step is applied by cross rolling instead of unidirectional rolling. The evaluation of tensile properties revealed that all cold rolling and annealing routes lead to significant improvements of mechanical properties in terms of strength and plasticity, the influence of cross rolling being more prominent again. Moreover, the cross rolling and annealing route led to a remarkable strength-ductility balance, which revealed the opportunities that this route can offer for the improvement of mechanical properties of austenitic stainless steels. Accordingly, the results of the present work may shed light on the further utilization of cold rolling route and annealing treatment.

Sustainable engineering of human hair fiber-composite in engineering application

The hybrid composite material, resulting from the fusion of human hair and Kevlar 29 synthetic fiber in a 10:1 ratio, reinforced with epoxy resin using the hand layup technique, underwent meticulous mechanical and thermal testing. The investigation encompassed tensile, flexural, and impact property evaluations, elucidating a notable enhancement in mechanical strength with a diminishing synthetic fiber content. Concomitantly, the composite exhibited commendable heat resistance in heat deflection tests, making it potentially suitable for applications in elevated temperature environments. Water absorption properties were scrutinized, revealing a correlation between reduced synthetic fiber content and diminished water absorption, implying heightened durability in diverse conditions. Microstructure analysis through SEM provided intricate insights into the internal composition. In summation, the composite, featuring a higher proportion of natural fibers and a lower proportion of synthetics, demonstrated superior mechanical attributes, optimal heat resistance, and reduced water absorption, showcasing its applicability in automotive and engineering domains, particularly in the fabrication of vehicle panels and components. The aim of this research represents a significant advancement in composite materials, offering a cost-effective solution that balances mechanical strength and thermal resistance. It suggests the potential for high-performance materials by combining natural and synthetic fibers, promising versatility across various applications.

Evaluation of tensile properties of ABS material specimen using commercial and manufactured filaments in FDM process

Acrylonitrile butadiene styrene (ABS) is the most common of engineering plastic materials; it is copolymer of Styrene-Acrylonitrile and butadiene styrene in special form. It is widely used in substantive and Additive Manufacturing (AM) applications. AM is a promising manufacturing technology that can fulfill future needs as products and their configurations are changing day by day. Fused Deposition Modeling FDM is an AM technique that fabricates parts layer upon layer. This paper analyses the effect of different process variables and orientations on the tensile properties of the FDM manufactured specimens. Standard specimens are printed using commercial ABS and manufactured ABS filaments for analysis of tensile properties. The ABS filament is fabricated using a mini filament extruder. After modeling, the specimens are printed using an FDM printer. The tensile testing of specimens is carried out on the Instron 3360 table frame UTM machine. Tensile properties obtained for different specimens are presented.

Evaluation of Tensile Properties and Formability of Al 6061 Alloy Processed by Various Semi-solid Techniques

Evaluation of Tensile Properties and Formability of Al 6061 Alloy Processed by Various Semi-solid Techniques

An improved analysis of small punch deformation for evaluating tensile properties

Small punch (SP) method is a promising technique for evaluating tensile properties using small volumes of test material, yet its applicability is bound by large errors in estimation of tensile yield strength (YS) using the yield force (FY) determined by the existing two tangent, offset or bilinear function fitting methods. In this study, a yield force (FY) based on the occurrence of yielding across the specimen thickness is identified through finite element analysis and a methodology is formulated for determination of FY from experimental data, supported with acoustic emission (AE) technique. The YS-FY correlation for various structural steels, Inconel and Aluminium exhibit excellent linearity and standard errors within ±7 %. Based on the onset of plastic instability in SP deformation at an inflection point (Fs, us) of force-deflection curve, the specimen deflection us is shown to correlate with tensile uniform strain better than parameter um (deflection at peak load). The tensile properties of neutron irradiated SS 316 evaluated from SP tests using the methodologies and SP-tensile correlations formulated in this work, are found to be within 6–8 % of the uniaxial tensile test results.

Role of customized scan strategies and dwell time on microstructure and properties of additively manufactured 316L stainless steel

Direct energy deposition (DED)-based additive manufacturing facilitates fabrication of medium-to-large functional parts. This study assesses the role of varying scan strategies and dwell time between each layer to control the cooling rate of 316L stainless steel produced by the laser-engineered net shaping-DED method. Customized print patterns were designed, keeping other optimized print parameters constant to obtain printed parts with better dimensional tolerance. The parts, which were >99% dense, were fabricated in a controlled argon environment. A heterogeneous microstructure consisting of a cellular columnar and equiaxed substructure was obtained. Two-dimensional X-ray diffraction revealed the presence of a single-phase γ-austenitic FCC phase. A refined microstructure with less elemental segregation was noticed with an increase in dwell time between the print layers. Internal defect analysis using X-ray micro-computed tomography revealed low lack-of-fusion voids along the build direction without any micro-cracks, which is attributed to higher cooling rates between subsequent print layers. As demonstrated in a mechanical performance evaluation of tensile and micro-hardness properties, better performance can be achieved by controlling the cooling rate and customizing deposition patterns.

Evaluation and prediction of tensile properties of 3D‐printed continuous carbon/Kevlar fiber‐filled composites by coaxial hybrid process

AbstractContinuous hybrid fiber‐reinforced composites (CHFRCs) have excellent mechanical properties, and strong designability, and are widely used in aerospace and other fields. The development of 3D printing technology offers novel directions in the design and manufacture of complicated CHFRC components in aerospace. For this purpose, this study focused on the design and characterization of hybrid continuous fiber‐reinforced composites prepared by 3D printing. The rapid mold‐free integrated manufacturing of hybrid continuous Kevlar/carbon fiber‐reinforced composites was realized by coaxial hybrid 3D printing technology. The regulation and mechanism of tensile properties of 3D‐printed CHFRCs were elucidated. The tensile strengths of 3D‐printed CHFRCs were enhanced by up to 15.3% and 92.4%, respectively, compared to single continuous carbon and Kevlar fiber composites produced by the same process parameter. A new tensile modulus predicting method for 3D‐printed CHFRCs was proposed. It mitigated the influence of complex interfacial characteristics on mechanical property prediction and achieved precise estimation of the tensile modulus of 3D‐printed CHFRCs. This will provide the theoretical support for the application and development of 3D‐printed CHFRCs.Highlights Mouldless rapid manufacturing of coaxial hybrid fiber composites achieved. The tensile strength and modulus of the fiber composites are greatly improved. A new prediction method for the tensile modulus of 3D‐printed composites is proposed.

Effect of processing parameters on the defects, microstructure, and property evaluation of Ti-6Al-4V titanium alloy processed by laser powder bed fusion

In this study, we designed the processing windows for laser powder bed fusion (LPBF) of Ti-6Al-4V (Ti-64) alloy by using central composite design and made a detailed investigation into the influence of processing parameters on the defects. The purpose is to investigate the effect of defects on mechanical properties. It was found that insufficient energy density could lead to the formation of lack of fusion (LOF) defects and produce non-melted powders on the surface, while excessive energy density could lead to cracks that were detrimental to mechanical performance. In addition, the microstructural evaluation found that relatively low energy density could lead to shorter columnar prior-β grains, while prior-β grains in the sample processed by the high energy density extended almost the entire height of the cross-section, which could lead to the strong mechanical property anisotropy. The prior β grains are formed by heterogeneous nucleation on the partially melted material powder. As the energy input increases, all the powder powders in the molten pool can be melted so that these particles do not act as nucleation sites and the prior β grain can grow through more layers without forming new grains being able to nucleate. The prior β-grain in as-built Ti-64 samples consisted of acicular α’ martensite with myriads of lattice distortions, as a precursor to a phase transition, which lead to strong tensile strength and poor ductility. Annealing heat treatment promoted the improvement of the ductile performance of LPBF Ti-64. Overall, this study provides comprehensive views on the effects of processing parameters (laser power, scanning speed, and hatch distance) on the internal (pores and LOF) and external (unmelted powder, sintering neck, and crack), defects, microstructure, and tensile property evaluation of LPBF Ti-64, which offer insights for the development of additive manufactured titanium alloys with excellent mechanical property.

Evaluation of tensile properties and cracking potential evolution of fly ash-cement mortar at early age based on digital image correlation method

The early-age tensile properties and shrinkage behaviors of mortar are important to investigate its early-age cracking potential. This study employs the digital image correlation method to quantify the tensile properties and shrinkage behaviors of fly ash-cement mortars at early age, aiming to reveal the effect of fly ash on the mortar's cracking potential evolution. Fresh mortars with varying fly ash (FA) contents (0%, 10%, 20%, 30%) undergo comprehensive tests, encompassing tensile strength, ultimate tensile strain, plastic shrinkage, mass loss, and damage assessment within 90–180 mins after casting. The results show that FA could enhance early-age ultimate tensile strain and extend the time for the mortar to maintain plasticity while reducing early-age shrinkage strain and mass loss. The mortar's cracking risk is potentially linked to its setting time. The rheological state of mortar gradually changed from plastic to non-plastic after initial setting, and the ultimate tensile strain stabilized, but the shrinkage strain increased rapidly, which resulted in a greater risk of shrinkage-induced cracking. Furthermore, after 180 mins of curing, the damage index of the fly ash-cement mortar (10% FA) was 1.6 times that of pure Portland cement mortar, whereas the damage indexes of the fly ash-cement mortars with 20% and 30% FA contents are approximately equivalent to 82% of the pure Portland cement mortar's damage index. This indicates that incorporating more than 20% fly ash is beneficial in reducing the risk of plastic shrinkage-induced cracking in mortar.

Retracted: Evaluation of Microstructure, Hardness, and Tensile Properties: A Comparative Study of Stir Cast and Extruded Al7005/Glass-/Fly-Ash-Reinforced Hybrid MMCs

Retracted: Evaluation of Microstructure, Hardness, and Tensile Properties: A Comparative Study of Stir Cast and Extruded Al7005/Glass-/Fly-Ash-Reinforced Hybrid MMCs

Three-dimensional structural characterization and mechanical properties of bamboo parenchyma tissue

Bamboo is predominantly composed of parenchyma and fibers, with parenchyma constituting approximately 52% of the bamboo culm wall. The bamboo fibers function as the primary load-bearing elements, its structure and performance have been studied in detail. However, investigations concerning the structure and mechanical properties of parenchyma tissue remain limited. Consequently, this study focuses on the comprehensive characterization of the three-dimensional (3D) structure of bamboo parenchyma. Additionally, the study encompasses the evaluation of tensile and compressive properties of parenchyma tissue, along with an analysis and discourse on failure mechanisms. Parenchyma cells can be categorized into two types: long cells, accounting for approximately 89.37%, and short cells. The measured tensile strength and elastic modulus of the parenchyma tissue are 48.81 MPa and 706.48 MPa, respectively. The propagation of cracks leading to tensile failure predominantly occurs along the middle lamella, accompanied by partial penetration through cell walls. Concerning parenchyma tissue compression, three discernible stages can be identified: the elastic stage, plateau stage, and densification stage. The axial load-bearing capacity of parenchyma tissue exceeds that of the tangential and radial orientations. Axial compressive strength and elastic modulus of the parenchyma are measured at 18.82 MPa and 5.24 GPa, respectively. Compression failure modes in parenchyma tissue encompass compression bending and cell fracture, shear failure of the middle lamella, and detachment and debonding of the cell wall. The comprehensive structural and mechanical parameters derived from this investigation provide valuable insights for the development of numerical models and understanding the various mechanical properties of bamboo.

On the evaluation of uniaxial tensile and fracture properties of Ti‐6Al‐4V by spherical indentation tests with different calculation models

AbstractThis study assessed the efficacy of models in predicting uniaxial tensile and fracture properties of Ti‐6Al‐4V (TC4) alloys via spherical indentation tests (SITs). Four models, including one empirical, one numerical, and two analytical, were selected as representatives to evaluate uniaxial tensile properties. A series of experiments were conducted on TC4 alloys obtained from three manufacturing processes: selective laser melting (SLM), forging, and welding. The empirical model underestimated the material's strength, while the other models were mostly conservative, with errors within 10%, acceptable for engineering applications. However, although the incremental model is able to provide a desirable result, it may be inaccurate for calculating the yield strength. Thus, the source of errors in each model was thoroughly investigated through theoretical analysis and finite element calculations. Additionally, based on the results of optimal strength assessment, this study validated the effectiveness of the critical stress model to evaluate the fracture toughness of TC4 alloys.

Evaluation of wet tensile shear strength and surface properties of finger-jointed acetylated beech (Fagus sylvatica L.) laminated veneer lumber

Experiments on finger-jointing acetylated beech (Fagus sylvatica L.) laminated veneer lumber (LVL) have been made. The specimens were examined on its wet tensile shear strength (TSS) using three adhesives, including phenol resorcinol formaldehyde (PRF), one-component polyurethane (PUR) (without primer), and melamine urea formaldehyde (MUF). Contact angles (CA) of uncured and drop-applied MUF, PRF, and PUR adhesives on freshly cut finger-joints were evaluated. Surface roughness was measured using a laser-scanning-microscope (LSM). Results showed that PRF bonded acetylated specimens had highest wet TSS, followed by specimens with PUR bonding. MUF performed poorly, which was most likely caused by its inadequate water resistance and changes in chemical reactions due to remaining acetic acid. Acetylated finger-joints had a topography similar to untreated joints. Moreover, CA were just barely lower for MUF and PRF on acetylated wood than on untreated references.

Evaluation of microstructure and tensile properties of Mg–5Zn-xZr-yCa alloys

In this work, an attempt was made to study the synergetic effects of changes in alloying elements including Zr and Ca, as well as the hot extrusion process on the microstructure, texture, and mechanical properties of Mg–Zn-xZr-yCa (x= 0.2 and 0.8 wt %; and 0<y<2) alloy. To do so, a variety of tests (OM, SEM, EBSD, EDS, TEM, APT, hardness and tensile tests) were performed after sample preparation. It was shown that Ca/Zr ratio plays an essential role in modifying the microstructure and mechanical properties of the alloy. For Ca/Zr<1, the grains size was remarkably refined to 1.2 μm, the wrought texture was moderately weakened, and the mechanical properties were significantly increased to 429 MPa. However, for Ca/Zr>1 grain size was almost unchanged, the texture of hot-extruded alloys became more equiaxed after hot extrusion, and tensile strength decreased compared to with Ca/Zr=1. Microstructural analysis revealed that Zr-bearing phases (Zn22Zr and Zn39Zr5) and solute theory were the dominant mechanisms of grain refinement in the as-cast state. An atom probe tomography technique was utilized to assess the segregation of solute elements into the grain boundaries. It was shown that particle stimulated nucleation is not likely to be the main mechanism of texture weakening of extruded alloys; and the solute segregation into grain boundaries facilitates this phenomenon. Finally, it was seen that values of yield and ultimate tensile strengths of Mg–5Zn-0.8Zr-0.5Ca were 372 and 429 MPa, respectively.

Evaluation of tensile and flexural properties of woven glass fiber/epoxy laminated composites oriented in edgewise and flatwise directions

In this study, the tensile and flexural properties of skin-core-skin woven glass fiber/epoxy laminated composites were conducted. Six plies (laminae) for the skins and twenty-four plies for the core were hand-laid up. All plies used had the same dimensions and the same elastic strength where the skins’ plies kept in flatwise direction while the core’s plies oriented in edgewise and flatwise to study the effect of plies alignments and hence loading direction i.e., edgewise (in-plane) and flatwise (out-of-plane) on the materials characteristics. It was observed that the composites oriented in edgewise position had the highest strength of 186 MPa (enhancement 59%) and deformed at higher loads with minor displacements compared to the flatwise strength of 117 MPa. The SEM analysis of the tensile’s fracture surface showed two dominant toughening mechanisms are debonding (fiber pullout) and fiber breakage, while interlaminar/intralaminar delaminated yarns was observed in the flexural fracture surface.

Evaluation of tensile, thermal, and biological properties of natural rubber‐based biocomposite with biosilicate and 45S5‐K bioglass

AbstractThe objective of this work was to develop new NR‐based biocomposite containing BioS and/or BL0 particles, which exhibit better tensile response, biocompatibility, and bioactivity for biomedical applications. Morphological, tensile, thermal, and biological tests were performed on the biocomposites to evaluate the influence of BioS and BL0 particles on the properties of the NR matrix. According to TG/DTG tests, the decomposition profiles of the NR/BioS and NR/BL0 biocomposites were similar to those of NR, whose main event could be seen in the 290–450°C temperature range, indicative of NR's structural degradation. Tensile analysis demonstrated that the addition of BioS or BL0 to the NR‐based biocomposite improved the elastic modulus and the tensile strength at break (σat break) in comparison to NR. The σat break value of the NR matrix increased from 0.99 ± 0.06 MPa to 1.84 ± 0.09 and 2.29 ± 0.04 MPa for the NR/BioS and NR/BL0 specimens with 30 wt%. Indirect cytotoxicity testing revealed that NR, NR/BL0, and NR/BioS biocomposite specimens promote the attachment of MSCs cell, that is, greater than 70% viability as defined in ISO 10993‐5:2009. The results indicate that BioS and BL0 particles have improved the tensile response and biological properties of the NR matrix, resulting in a range of potential biomedical applications.

Size effects on tensile properties of Chinese reactor pressure vessel steels and its semi-empirical normalization

As one of major barriers of nuclear reactors, reactor pressure vessels (RPVs) are subjected to neutron irradiation and faced with degradation during operation, therefore their mechanical properties are vital to the safety evaluation of nuclear power plants. Due to the radioactivity of specimens and limited space in the reactors, small tensile specimens are expected to be utilized for tensile property evaluation of RPV steels. However, the size effect would influence the tested tensile results and precise evaluation of mechanical properties of materials. This research is aimed to study the size effects of Chinese RPV steels in detail. It is found that size parameters of tensile specimen will affect the yield behavior, fracture behavior, tensile strength and the elongation, which causes are discussed as well. Moreover, a semi-empirical normalization model is built to normalize the total elongation after fracture of small specimens to the standard industrial specimens, which could make contributes to the normalization of results from different size specimens and serve for the design of small specimen of Chinese RPV steels in industry.

Evaluation of tensile properties of spherical shaped SiC inclusions inside recycled HDPE matrix using FEM based representative volume element approach

In the current study, a FEM-based representative volume element (RVE) technique is used to evaluate the elastic modulus of recycled high-density polyethylene (rHDPE) filled spherical-shaped shaped silicon carbide (SiC). In the ANSYS 2019, the material designer (MD) module is used to generate a 3D RVE of 500 × 500 × 500 μm cuboid, with randomly dispersed spherical SiC particles (i.e., 10, 15, 20, and 30% volume fractions) inside rHDPE. The Young's modulus values extracted from the RVE technique at various volume % are substantially nearer to experimental data than other micromechanical models. The tensile performance of the composite is simulated, and it was noted that the maximum equivalent stress of 4.1133 MPa for rHDPE/30% SiC composite, which is decreased to 13.8, 7.8 and 6.8% for rHDPE/10% SiC, rHDPE/15% SiC and rHDPE/20% SiC composite respectively. The results are astounding for immediate application in the relevant field of interest.

Evaluation of tensile properties of early-age concrete-block masonry assemblages

Masonry is one of the most traditional and economical modes of construction worldwide. Although many codes and standards are available to evaluate fully-cured masonry assembly properties for the design of masonry structures, there is a gap in understanding the properties of freshly laid masonry and the design of newly constructed unsupported masonry walls. Early-age (within the first seven days) masonry at the construction site possesses reasonably high compressive strength but considerably low flexural tensile strength, making it vulnerable to lateral loads due to wind, earthquake, and adjacent constructions. This has resulted in numerous incidents of structural damage and injury to workers leading to more stringent and conservative construction bracing techniques. In this paper, the tensile properties of early-age concrete block masonry have been assessed by conducting comprehensive numerical and experimental studies on mortar and masonry assemblage. Outlier analysis has been applied to the experimental data to minimize uncertainties and biases. The modulus of elasticity and tensile strength of the masonry assemblages against the curing time has been obtained using a statistical analysis conducted over a large sample size. The results show that the tensile strength of masonry remains nearly insignificant until 3–7 h, then increases logarithmically. It is also observed that the bond between the mortar and blocks is the weakest part of the masonry assemblages, and the failure happens in the unit-mortar interface bond rather than in the fresh mortar. The modulus of elasticity and tensile strength of early-age masonry assemblages are 38% and 18% of the corresponding properties of early-age mortar material alone, respectively. Therefore, the quantification of assembly properties cannot be ascertained from material testing alone within seven days of construction. It is anticipated that the proposed research will provide valuable design properties leading to improved guidelines needed to design control devices (e.g., temporary bracing) for concrete-block masonry construction.

Evaluation of Tensile Properties Using Uni-Axial Testing and Correlation with Microstructure of AA2014 alloy

AA2014 is most widely used metal among the aluminium alloy series due to its exceptional corrosion resistance, low density rate, and it can maintain high strength and toughness at various temperatures. So, these materials have their application in the aerospace, military and the automotive sector. The present work focuses on evaluating the mechanical properties such as ultimate Tensile strength (UTS), Yield strength (YS), and percentage of elongation using Uniaxial Tensile test. The three controllable factors used in the present study are temperature ranging from 200 to 300°C with 50°C increment, orientation 0,45,90 degree relative to the rolling direction and strain rate 0.001,0.01 and 0.1mm/sec. A total of 27 experiments were planned and conducted based on the design of experiments. Experimental results show that with increase in strain rate increasing of material properties furthermore with increase in temperature decrease of material properties and increase in the percentage of elongation was observed. In addition to that ANOVA analysis was carried out and noticed that strain rate is most effecting parameter for UTS and temperature is most effecting parameter for YS and percentage elongation. The fracture specimens from uniaxial test are investigated for type of fracture through microstructural studies