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Debris flow hazards are often interpreted through back-calculated simulation analysis or empirical methods. The mobility of a debris flow is greatly influenced by mechanical and hydrological parameters. The strength parameters play important roles in the debris flow initiation and flow stages. In particular, the rheological parameters of yield strength and plastic viscosity directly affect the debris flow runout distance and velocity. One of the most important parameters to consider when evaluating debris flow hazards is the shear strength. This strength is called the residual shear strength in the failure stage and the yield strength in the post-failure stage. The residual shear strength obtained from ring shear tests can be related to the initiation of mass movements; the yield strength obtained from rheological tests can be related to the mobilization of debris flows. The residual shear stresses obtained from ring shear tests of weathered soils typically range between 10 and 100 kPa and strongly depend on the normal stress and shear velocity. When progressive slope failure (i.e., strain-softening behavior) occurs at a relatively shallow slope depth (e.g., < 1 m), the soil strength ranges from approximately 5–10 kPa. If the liquid limit state (i.e., solid‒liquid transition) is reached, the shear strength of the soil is approximately 2 kPa. Once the soil fails and mixes with ambient water along the slip surface, the yield strength decreases dramatically, resulting in high mobilization. A suggestion on how strength parameters can be applied to estimate debris flow mobility is presented by considering the 2011 Miryang debris flow, which occurred in weathered soil deposits in Miryang city, Republic of Korea. The best approach for debris flow yield strength estimation would be to consider the residual shear strength in the initiation stage, the yield strength in the flow stage, and the reduction in yield strength with the entrainment effect of the flow in the rapid fluidization stage. [ABSTRACT FROM AUTHOR]

FeCrAl alloy is considered a promising material for light water reactor fuel cladding due to its excellent elevated temperature oxidation resistance and radiation performance. The effects of 0.21 wt% Nb or 0.23 wt% La additions on the microstructure, second phase, yield strength and toughness of FeCrAl alloy are studied. The morphology and number fraction of inclusions in FeCrAl alloys are analyzed. The addition of 0.21 wt% Nb in FeCrAl alloy promotes the precipitation of nanoscale (Fe,Cr)2(Nb,Ti) Laves phase and refining grain size. The addition of La‐modified Al2O3 and MgO·Al2O3 inclusions to La2O3 and LaS, and La2O3 is favorable to promote the heterogeneous nucleation of α‐Fe. The fracture mode of the FeCrAl alloy with 0.21 wt% Nb or 0.23 wt% La transitions from dimple fracture and quasi‐cleavage fracture to dimple fracture, in comparison with Nb‐free or La‐free FeCrAl alloy. Nb and La additions improve the yield strength and toughness of FeCrAl alloy. The addition of Nb exhibits a more pronounced strengthening effect on FeCrAl alloy compared with the addition of La. [ABSTRACT FROM AUTHOR]

The yield strength and Young's modulus of lattice structures are essential mechanical parameters that influence the utilization of materials in the aerospace and medical fields. Currently, accurately determining the Young's modulus and yield strength of lattice structures often requires conduction of a large number of experiments for prediction and validation purposes. To save time and effort to accurately predict the material yield strength and Young's modulus, based on the existing experimental data, finite element analysis is employed to expand the dataset. An artificial neural network algorithm is then used to establish a relationship model between the topology of the lattice structure and Young's modulus (the yield strength), which is analyzed and verified. The Gibson–Ashby model analysis indicates that different lattice structures can be classified into two main deformation forms. To obtain an artificial neural network model that can accurately predict different lattice structures and be deployed in the prediction of BCC-FCC lattice structures, the artificial network model is further optimized and validated. Concurrently, the topology of disparate lattice structures gives rise to a certain discrete form of their dominant deformation, which consequently affects the neural network prediction. In conclusion, the prediction of Young's modulus and yield strength of lattice structures using artificial neural networks is a feasible approach that can contribute to the development of lattice structures in the aerospace and medical fields. [ABSTRACT FROM AUTHOR]

In this article, the yield strength, tensile strength, and the microstructure of the wrought aluminium alloy 7449 rolled thick plate have been studied through thickness under different temper conditions. For all heat treatments, it has been proven that the yield strength and tensile strength values increase from the surface to the centre. The largest difference between the centre and the surface, in both properties, occurs in the case of a sample aged at room temperature for 120 h (TTA temper). The sample artificially aged at 120 °C for 24 h (TTB temper) shows the best strength-gradient relationship of the tensile properties through the thickness. Metallographic characterisation carried out by optical and scanning electron microscopy shows much finer elongated grains in the region near the surface of the plate than in the centre, with incipient recrystallisation in the area near the surface. In addition, electron backscattered diffraction technique, used for micro-texture analysis, has proven the presence of a gradient of crystallography texture in the plate. This explains the yield strength gradient, since the rate of change of the Taylor factor through thickness correlates with the rate of the change of yield strength in the longitudinal direction for the samples studied. [ABSTRACT FROM AUTHOR]

Most premature failures of double-pass weldments are associated with limited knowledge of the mechanical and microstructural evolution following the welding process. Thus, this study aims to investigate the effect of double-pass tungsten inert gas welding on the mechanical and microstructural properties of type AISI 1008 mild steel joints. Double-pass TIG welding in butt joint configuration was adopted to weld the plates maintaining a 2.5 mm root gap in between plates. The double-pass tungsten inert gas welded AISI 1008 joints showed improved ultimate tensile strengths in contrast to the unwelded counterpart, with the least joint efficiency of 82.67 % (weld W3). An increase in the heat input led to a corresponding increase in the weld metal hardness, whereas the hardness of the heat-affected zones increased first and then decreased. The internal geometry of the welds reveals an increase in the bead width, height of reinforcement, width of the heat-affected zone, and weld metal area as the heat input increases. Lastly, the microstructural evolutions of the weld metal zones were primarily dominated by widmanstatten ferrite, acicular ferrite, and pearlite structures, accounting for the enhanced tensile strength and hardness of the joints. Meanwhile, the heat-affected zones were characterised by coarse columnar dendrite structures resulting in lower hardness values. This study gives an insight into the mechanical and microstructural properties of the industry's most frequently used steel grade, which has not been given much attention in past studies. The research finding enriches the welding theory of A1SI 1008 steel for industrial and academic benefits. [ABSTRACT FROM AUTHOR]

Remote operated vehicle (ROV) deployment baskets are used to store ROV installation tools on land and in the deepwater. In addition to the convenience of ROV operation, it also provides protection for ROV installation tools, which can be well adapted to the far-reaching sea environment, and is an important component of subsea production system. Its deepwater installation operation has high risks and strict requirements, so it is important to study its strength performance in the whole installation process to ensure the smooth operation of the whole subsea production system. Based on a variety of typical deepwater working conditions of ROV deployment basket used in Lingshui water gas field of the South China Sea, the design load was calculated, and then the finite element modeling analysis was carried out to calculate the stress response under different load conditions, and the yield strength of the structure was checked to ensure that the overall structural strength met the safety requirements. The calculation results show that the structural yield strength of the ROV deployment basket meets the specification requirements under various lifting conditions, impact conditions and transportation conditions. On this basis, the design of the ROV deployment basket used on site is guided, and the whole offshore installation and underwater operation are safe and reliable. The research results can provide theoretical basis and technical reference for the structural design and deepwater installation of ROV deployment baskets and similar underwater structures. [ABSTRACT FROM AUTHOR]

This paper investigates the metallurgical factors contributing to the non-conformance in mechanical properties observed in Maraging 250 steel (M250) holding pins after the aging process. Results revealed a significant difference in the mechanical properties between the aged as-received pins and the aged as-annealed rods. Microstructural analysis highlighted the influence of processing conditions, including straightening and centerless grinding, on the material's behavior during aging. Moreover, the presence of retained austenite was found to exceed specified limits in the as-received rods that exhibited mechanical property non-conformance. In this study, a comprehensive metallurgical analysis was conducted to understand the factors contributing to the non-conformance in mechanical properties of aged M250 holding pins and essential steps required for improving the reliability and performance of these components. By gaining insights into the microstructural changes and associated material behavior, appropriate process optimizations and quality control measures can be implemented to ensure the attainment of desired mechanical properties. [ABSTRACT FROM AUTHOR]

Based on numerical simulation and fatigue tests, different types of crack were simulated and local full-scale specimens of typical fatigue details in steel bridge deck were designed for drilling. The relationship between the reasonable hole diameter, stress intensity factor K at the crack tip and yield strength σys of the base metal was explored. The result demonstrates that the reasonable hole diameter is linearly related to $K^ 2/\sigma _{ys}^ 2$ K 2 / σ ys 2 . The larger the ratio of KIII/KI, the smaller the reasonable diameter required. Considering that KIII cannot be measured in real bridges, taking KI2/σys as the basis for diameter selection can ensure a large surplus. The method of determining the hole diameter by K and σys is applicable when the crack length is relatively short compared with the boundary size. In addition, the stress intensity factor measured by the two-strain-gage method is slightly higher than that calculated by extended finite element method, with an average error of about 10%, which has the accuracy required for real-bridge application. [ABSTRACT FROM AUTHOR]

Twinning-induced plasticity (TWIP) steel is an ideal material for impact-resistant structures and energy absorption because of its high product of strength and elongation. However, compared with other advanced high-strength steels, the relatively low yield strength of TWIP steel is one of the important shortfalls that significantly limits its engineering applications. To enhance the comprehensive properties of TWIP steel, a machine learning design strategy that integrated comparative modelling, SHAP analysis, and multi-objective optimization were adopted in this study. Initially, various machine learning algorithms were compared for their predictive accuracy based on normalized data (273 entries) regarding the microstructure and properties of TWIP steel. Then, performance prediction models for yield strength, tensile strength, and elongation were established. SHAP analysis was subsequently employed to assess the significance and explicit laws of composition and microstructures in these three target properties, identifying key elements that enhance the overall performance. Furthermore, two new TWIP steels with high yield strengths and high products of strength and elongation were developed via multi-objective optimization. Under conventional hot forging + hot rolling + cold rolling + annealing processes, the two designed TWIP steels had yield strengths of 585 MPa and 560 MPa, tensile strengths of 1055 MPa and 1101 MPa, elongations of 55% and 58.5%, and products of strength and elongation of 58.0 GPa% and 66.4 GPa%, respectively. The yield strengths of the designed TWIP steels significantly improved while maintaining a reasonable product of strength and elongation. This work provides important references for the rational development of new TWIP steels. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bone tissue engineering shows potential for regenerating or replacing damaged bone tissues by utilizing biomaterials renowned for their biocompatibility and structural support capabilities. Among these biomaterials, polycaprolactone (PCL) and polylactic acid (PLA) have gained attention due to their biodegradability and versatile applications. However, challenges such as low degradation rates and poor mechanical properties limit their effectiveness. Dimethyl sulfone (DMSO2) has emerged as a potential additive to address these limitations, offering benefits such as reduced viscosity, increased degradation time, and enhanced surface tension. In this study, we investigate tailored composites comprising PLA, PCL, and DMSO2 to enhance mechanical properties and hydrophilicity. Through material characterization and mechanical testing, we found that the addition of DMSO2 led to improvements in the yield strength, modulus, and hydrophilicity of the composites. PCL and DMSO2 10, 20, and 30 wt% were premixed, and 20 wt% PCL + 10, 20, and 30 wt% DMSO2 were mixed with PLA. Specifically, PLA/PCL/DMSO2 composites exhibited higher yield strengths and moduli compared to pure PLA, pure PCL, and PLA/PCL composites. Moreover, the hydrophilicity of the composites increased with DMSO2 concentration, facilitating cell attachment. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of –COOH and –COH bands in PLA/PCL/DMSO2 composites, indicating chemical interactions between DMSO2 and the polymer matrix. Fractography analysis revealed enhanced interface adhesion in PLA/PCL/DMSO2 composites due to the hydrogen bonding. Overall, this study demonstrates the potential of PLA/PCL/DMSO2 composites in bone tissue engineering applications, offering improved mechanical properties and enhanced cell compatibility. The findings contribute to the advancement of biomaterials for additive manufacturing in tissue engineering and regenerative medicine. [ABSTRACT FROM AUTHOR]

The use of acrylonitrile butadiene styrene (ABS) in additive manufacturing applications constitutes an elucidating example of a promising match of a sustainable material to a sustainable production process. Lean-and-green datacentric-based techniques may enhance the sustainability of product-making and process-improvement efforts. The mechanical properties—the yield strength and the ultimate compression strength—of 3D-printed ABS product specimens are profiled by considering as many as eleven controlling factors at the process/product design stage. A fractional-factorial trial planner is used to sustainably suppress by three orders of magnitude the experimental needs for materials, machine time, and work hours. A Gibbs sampler and a neutrosophic profiler are employed to treat the complex production process by taking into account potential data uncertainty complications due to multiple distributions and indeterminacy issues due to inconsistencies owing to mechanical testing conditions. The small-data multifactorial screening outcomes appeared to steadily converge to three factors (the layer height, the infill pattern angle, and the outline overlap) with a couple of extra factors (the number of top/bottom layers and the infill density) to supplement the linear modeling effort and provide adequate predictions for maximizing the responses of the two examined mechanical properties. The performance of the optimal 3D-printed ABS specimens exhibited sustainably acceptable discrepancies, which were estimated at 3.5% for the confirmed mean yield strength of 51.70 MPa and at 5.5% for the confirmed mean ultimate compression strength of 53.58 MPa. The verified predictors that were optimally determined from this study were (1) the layer thickness—set at 0.1 mm; (2) the infill angle—set at 0°; (3) the outline overlap—set at 80%; (4) the number of top/bottom layers—set at 5; and (5) the infill density—set at 100%. The multifactorial datacentric approach composed of a fractional-factorial trial planner, a Gibbs sampler, and a neutrosophic profiler may be further tested on more intricate materials and composites while introducing additional product/process characteristics. [ABSTRACT FROM AUTHOR]

The effect of silicon dioxide nanoparticles on the rheology of aqueous solutions of xanthan gum was studied. Tests were carried out on a rotational viscometer and by the oscillatory method on an Anton Paar rheometer. Additions of nanoparticles up to 2 wt.% to solutions containing up to 1 wt.% gum were analyzed. In the studied concentration ranges, the influence of nanoparticles maintains the shape of the flow curves and viscosity curves, introducing small changes. It was shown that with increasing concentration of nanoparticles, the elastic modulus of suspensions, the values of their yield strengths and flow points increase. At the same time, the pseudoplasticity index practically does not increase, leading to the manifestation of a brittle rupture with increasing load in the oscillatory test of the suspension. The storage modulus at a nanoparticle concentration of 1% takes on a two-stage form, and at a concentration of 2% it forms a hysteresis curve, indicating a brittle rupture of the material. It was shown that the effect of the conformational transition is about 30% and decreases with increasing flow shear rate. [ABSTRACT FROM AUTHOR]

In the presents research an experimental investigation was conducted on the resistance seam welding of thin sheets of thickness 0.2 mm for packaging application. The most difficult issues in such sectors are reducing product weight without compromising weld strength. The machines used in such industries are of certain specifications. Major modifications in the machine are very costly. Thus, the industrial need is to regulate the machine in the given specification for better productivity and high quality of the product. Twenty sets of experiments were conducted on the industrial grade resistance seam welding machine in order to investigate the versatility of the machine and possible effect on the mechanical and microstructural properties of the resistance seam welded joint. The experiments were conducted in two parts. In the first part only current was varied (i.e. single factor experiment) keeping other parameters such as electrode wheel speed and welding voltage unchanged. In the second set of experiments, both current and electrode wheel speed were changed keeping voltage constant. Mechanical properties such as tensile strength, yield strength, breaking load, elongation at breaking were studied as the function of current and wheel rotational speed. The yield strength firstly increases up to 84 A and then decreases with increase in the welding current keeping other parameters fixed. The elongation at break also decreases with increasing current value. Microstructural properties were also analysed for the proper understanding of the process and potential effect on the various mechanical properties. [ABSTRACT FROM AUTHOR]

Welded yield strength is designed to be large enough to handle all forces and pressures on the joint and is designed to be as strong as the tube itself. Hence, the objective of this paper was to investigate the use of artificial neural network (ANN) to evaluate and forecast selected welding parameters on mild steel welded joints soldered by tungsten inert gas (TIG) using sixty (60) experimental data generated by replicating the design matrix from the Central composite Design (CCD) used for the ANN modelling. The welding current, welding voltage and gas flow rate were selected as process parameters and yield strength chosen as Response. Data obtained show that the R-value (coefficient of correlation) for training shows of 95.8% closeness, 99.2% for validation and 93.1% for testing respectively. The overall R-value obtained is 95.1% which showed that the developed model can accurately predict the value of strength. Results also showed that ANN is a highly effective tool for prediction of the Yield strength in TIG Mild steel weld. [ABSTRACT FROM AUTHOR]

The addition of alloying elements is a crucial factor in improving the mechanical properties of pure copper, particularly in terms of enhancing its yield strength and hardness. This study examines the influence of scandium additions (up to 0.27 wt.%) on low-alloyed copper. Following the casting and solution-annealing processes, the alloys were quenched in water to maintain a supersaturated state. The mechanical properties were evaluated by tensile tests to measure the yield strength and the dynamic resonance method to determine the modulus of rigidity. Additionally, X-ray diffraction was utilized to analyze changes in lattice parameters, elucidating the structural modifications induced by scandium. This study dissects the parelastic and dielastic effects underlying the solid solution hardening mechanism, providing insights into how scandium alters copper's mechanical properties. The findings align with the solid solution hardening theories proposed by Fleischer and Labusch, providing a comprehensive understanding of the observed phenomena. [ABSTRACT FROM AUTHOR]

To achieve an ultra-fine grained structure, 2 passes of constrained groove pressing (CGP) were performed on AZ31 Mg alloy sheets at a temperature of 250 °C. To examine the deformation and fracture behavior of the produced alloy sheets, tensile tests conducted at different temperatures ranging from 25 to 200 °C and strain rates varying from 0.001 to 0.1 s−1. The Box-Behnken design was utilized to conduct experiments, and the response surface methodology was employed to represent the output responses in terms of the key parameters. At a strain rate of 0.0505 s−1 and a temperature of 200 °C, the maximum elongation of 23% was observed, whereas, the material exhibited the yield strength of 128 MPa and the ultimate strength of 163 MPa. Ductile fracture morphology was noticed with increasing temperature. The %elongation slightly decreased as a result of the coarsening of grains at 250 °C. A specialized experimental setup incorporating heating systems was utilized to facilitate high-temperature constrained groove pressing (CGP) on materials that are difficult to deform. A systematic investigation was carried out to analyze the microstructure and mechanical properties of AZ31 Mg alloy sheets subjected to CGP. The study aimed to highlight the influence of the number of passes and thermal deformation on these properties. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Debris flow hazards are often interpreted through back-calculated simulation analysis or empirical methods. The mobility of a debris flow is greatly influenced by mechanical and hydrological parameters. The strength parameters play important roles in the debris flow initiation and flow stages. In particular, the rheological parameters of yield strength and plastic viscosity directly affect the debris flow runout distance and velocity. One of the most important parameters to consider when evaluating debris flow hazards is the shear strength. This strength is called the residual shear strength in the failure stage and the yield strength in the post-failure stage. The residual shear strength obtained from ring shear tests can be related to the initiation of mass movements; the yield strength obtained from rheological tests can be related to the mobilization of debris flows. The residual shear stresses obtained from ring shear tests of weathered soils typically range between 10 and 100 kPa and strongly depend on the normal stress and shear velocity. When progressive slope failure (i.e., strain-softening behavior) occurs at a relatively shallow slope depth (e.g.,

The mechanical properties, texture transformation, and mechanism of Al–Cu–Mn alloy during annealing were studied using three-dimensional orientation distribution function (ODF), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that the increase in yield strength after annealing at 200 °C is due to the decrease in the proportion of P and M textures and the increase in the proportion of Goss texture. The increase in the change rate of mechanical properties observed during annealing at 250 and 350 °C can be attributed to the higher proportion of M and P textures and the reduced proportion of Goss textures. Among them, the proportion of M texture increased significantly, and the Goss texture decreased significantly after annealing at 350 °C. This is because the structural energy density (Ev) value of the Goss texture is higher than that of the M texture at 250 °C and 350 °C. The Goss texture is in an unstable state of high energy order. The deformed Goss texture is unstable at high temperatures, leading to conversion into M and other textures. The EBSD and TEM analysis revealed that the hardness is mainly related to the change in dislocation density. When the annealing temperature is increased from 250 to 350 °C, the hardness is significantly reduced from 62 HV to 52 HV, and the dislocation density is reduced from 4.0 × 1014 ρ/m−2 to 2.4 × 1014 ρ/m−2.

The evolution of tensile properties and microstructure in three 9% Cr martensitic rotor steel with varying contents of W and Mo elements is investigated after aging at 630 °C for different durations, with a primary focus on the characteristics of martensite laths and blocks, grain boundaries, dislocations, and precipitates. The results indicate that the presence of W and Mo elements not only influences the precipitation and coarsening behavior of Laves phases but also that of M23C6 carbides, which differs from conventional beliefs. The elevated content of Mo and reduced content of W in the steel leads to a reduction in the equilibrium Cr concentration, promoting enhanced precipitation of Cr atoms and increases nucleation sites of M23C6 carbides. During the aging treatment, the M23C6 carbides in the 2.0W0.5Mo steel exhibits the highest content and the lowest coarsening rate. The strength of 9% Cr martensitic rotor steel is primarily enhanced through dislocation strengthening and grain boundary strengthening. The presence of fine M23C6 carbides effectively immobilizes dislocations and interfaces, resulting in the exceptional stability of the microstructure in the 2.0W0.5Mo steel and a minimal reduction in yield strength.

Brass sheet is added into the joining location in friction stir welding (FSW). Brass reinforced Al matrix composite is then formed in the FSW nugget zone with brass. A new microstructure based mechanical property model is proposed to predict both the microstructural evolutions and mechanical property changes in FSW with brass. The discrepancy between the numerical and experimental data is 0.77% for temperature, 2.2% for average grain size, and 6.4% for hardness. The change of temperature is very small in comparison of FSW and FSW with brass. However, compared to FSW, the hardness is obviously increased and the average grain size is decreased by 34.8% in FSW with brass in the nugget zone due to the pinning effect from the broken brass particles. The process parameters can be numerically tested to find the optimal design for experiment.

Based on magnetic fluids, new effective technical devices have been implemented, such as magnetic fluid bearings, seals, and dampers. The magnetic-viscous effect inherent to magnetic fluids can not only improve the properties of magnetic fluid units, but significantly complicate their operation after a long stop. This refers to the so-called «stop effect», which occurs due to an abnormally high limiting shear stress in a nanostructured liquid. The plastic properties of the magnetic fluid are experimentally studied depending on the following parameters: shear stress, temperature, structure formation time. The destruction of the nanostructure of the magnetic fluid begins after the shear stress exceeds a certain critical value. At stresses below the critical, but above the limiting shear stress, the displacement of the solid surface occurs by overcoming the boundary friction of the magnetic fluid on the solid surface. The experimentally established exponential course of the temperature dependence of the shear rate reflects the nature of the forces that determine the internal friction in the magnetic fluid.

Purpose. The study is aimed at evaluating the effect of the isothermal transformation temperature on the structure and properties of low-carbon steel. Methodology. The material for the study was a 3 mm diameter wire made of mild steel with the following chemical composition: 0.21% C, 0.47% Mn, 1.2% Si, 0.1% Cr, 0.03% S, 0.012% P. The 0.3 m long wire samples were subjected to austenitizing at 920 °C for 8...9 min, after which they were held isothermally for 11 min at temperatures of 650...200 °C, followed by cooling in air. The strength, plastic properties, and strain hardening coefficient were determined from the analysis of tensile curves. Findings. It was found that a decrease in the temperature of isothermal transformation, starting from 450...400 °C, increases the amount of Widmannstätten ferrite due to the disappearance of polyhedral ferrite grains. At the same time, the number of areas with locally located dispersed cementite particles similar to pearlite colonies increases, and bainite crystals appear. Against the background of a sharp decrease in the strain hardening coefficient in the range of 450...400 °C, the ability of the bainite phase to undergo plastic deformation should be considered one of the reasons for the delay in density reduction. Originality. The effect of steel hardening with a decrease in the pearlite transformation temperature is based on the grinding of ferrite grains, an increase in the amount of Widmannstätten ferrite, and the dispersion of pearlite colonies. The strengthening effect of steel with a bainite structure is based on an increase in the degree of supersaturation of the solid solution with carbon atoms and dispersion hardening by particles of the carbide phase. Practical value. The optimal structural state of steel intended for the manufacture of such critical elements as a support beam, railroad car bogie, etc. is a mixture of phase components with different dispersion and morphology, and their quantitative ratio is determined by the operating conditions of a particular product.

The yield strength of metallic materials is commonly estimated using linear superposition methods, but this method has limited adaptability to new materials. The mapping relationship between input and output in machine learning methods is difficult to quantify. This study employs a rapid screening method to identify the key strengthening mechanisms that influence the yield strength of typical homogeneous and heterogeneous metallic materials. A non-linear physical neural information network model is developed to describe the yield strength of heterogeneous structures, capturing the main parameters contributing to yield strength from selected physical quantity data. By considering the non-linear strengthening mechanisms arising from interactions among multiple strengthening mechanisms in heterogeneous metal structures, the microstructure and mechanical properties of eutectic high-entropy alloys are optimized through warm rolling and short-time annealing. By inducing microstructural spheroidization and introducing nanoscale precipitates, significant coupling effects of multiple strengthening mechanisms are achieved for eutectic high-entropy alloys. As a result, the yield strength increases by approximately 2.5 times, while plasticity remains nearly unchanged. Transmission electron microscopy, scanning electron microscopy, and electron backscatter diffraction observations provide evidence for the sources of these coupling effects. This study offers guidance for accelerating material design and exploring the physical relationship between microstructure and mechanical properties.

Introduction. The Republic of Belarus is one of the first countries on the territory of the CIS, which introduced European design standards (Eurocodes) on its territory, while preserving the effect of building standards developed on the basis of Soviet SNIP. The republic accumulated considerable experience in the practical application and comparative analysis of these two systems of standards. The relevance of this study is contained in the discovery of the most distinctive features of normative documents, on the basis of which it is possible to determine further directions of scientific research and improvement of domestic norms.Materials and methods. Analysis and generalization of experience.Results. The paper presents the results of generalization of the experience of practical application and comparative analysis of Eurocode and CP in relation to the design of steel structures. The analysis of partial factors, classification of cross sections, welded and bolted joints is given.Conclusions. Methodological approaches to checking limit states and ensuring the reliability of steel structures in CP and Eurocodes are very similar, but there are differences in the values and sets of partial factors. When designing steel structures according to Eurocode, the methods of classification of cross-sections of rolled profiles produced according to GOST or TS need to be adjusted. Eurocode 3 provides more possibilities in the design of welded and bolted joints.

After undergoing 75% hot deformation and 40% cold deformation, a variant of TWIP (Twin Induced Plasticity) steel with a composition of Fe–22Mn−2.7Al−0.95C−0.75Si (wt.%) was subjected to annealing at various temperatures (850 °C, 650 °C, 550 °C) for 20min. The recovery annealed C550 sample exhibited a yield strength of 1289.20 MPa, a tensile strength of 1442.29 MPa and an elongation of 30.78%. Characterization and comparison of the samples were conducted using XRD, SEM, EBSD, TEM and uniaxial tensile tests. The yield strength of the sample was assessed through different strengthening mechanisms to analysis the exceptional properties of the recovery annealed sample. Experimental findings indicate that the high-density dislocation and the refinement of slip bands in the recovery annealed C550 samples contribute to their superior performance compared to the partially and fully recrystallized samples.

Microstructure and mechanical responses of A357 aluminum alloy welding wires after different degrees of strain were studied. It is found that the grains are elongated and refined along the drawing direction, accompanying with cell structures and sub-grains with strain increasing. Meanwhile, the main contributions to the fibrous texture are Cube, Goss and Copper, i.e., and textures. With the increase of drawing strain, the volume fraction of the Copper texture first increases and then decreases, while that of the Goss texture increases monotonously. The yield strength sharply increases at low drawing strain, after reaching the maximum value of 144.7 MPa at the strain of 0.32 and it decreases slightly due to dynamic recrystallization. Interestingly, the elongation of the cold-drawn wires decreases steadily from 24.4% to 2.3% throughout the entire drawing process. In addition to the grain boundary strengthening and dislocation strengthening, the yield strength of the cold-drawn A357 wires is also impacted by the texture.

Aluminum metal-matrix composites (AMMCs) were prepared by dispersing TiO2 dispersoids of different volume fractions into an AA6063 matrix via stir casting and subjected to process-structure correlation studies. Four different samples based on weight ratio were considered herein: 99Al-1TiO2, 97Al-3TiO2, 95Al-5TiO2, and the as-received AA6063. Their mechanical properties namely, microhardness, tensile strength, and tribological behavior, were determined. In addition, the microstructure of the samples was also analysed. It was observed that the addition of 5% TiO2 particles enabled the AA6063 matrix to accommodate a higher strain energy while providing the required driving force to generate dislocations and substructures. Therefore, considering the plastic deformation, the ultimate tensile strength (sut) increased gradually with the addition of TiO2 (in weight%). The flow curves of the 95Al-5TiO2 sample showed the highest value of sut, whereas the as-received AA6063 matrix exhibited the lowest value. For linear elastic deformation, AA6063 showed the lowest yield strength (sys) as compared to the AMMC samples for all TiO2 weight% values; however, the variation in sys among the AMMC samples was minimal. The microhardness of the samples increased gradually with the addition of TiO2, and the percentage reduction in area at the fracture was largest for 95Al-5TiO2. The Taguchi's L9 array and variance analysis of the process parameters indicated that the material wear was largely affected by the normal load, followed by weight% of TiO2 and sliding speed. Wear surface characteristics, such as microvoids, delamination, microcracks, and wear debris, were qualitatively observed in all the AMMC samples. The overall strength improvement was attributable to the effects of addition of the dispersoids. During melt solidification, the TiO2 particles surpassed/pinned and hindered the grain growth, resulting in grainsize refinement. [ABSTRACT FROM AUTHOR]

Sintering is a critical step in the formation process of porous Ti. Porous Ti can be endowed with excellent mechanical properties by controlling sintering conditions. Porous Ti for liquid‑solid filtration with a 60% space holder was manufactured using vacuum distillation sintering, which uses Mg powder and Mg particles as the space holder under different sintering conditions. The microstructure, compressive property and bending property were characterized and tested, providing a reference for the preparation and performance optimization of porous Ti. The results show that with increasing of sintering temperature and time, the pore size of porous Ti decreases, the porosity decreases, and the pore spheroidizes. When the sintering temperature is below 1 150 ℃, the axial shrinkage of porous Ti is always greater than the radial shrinkage. The yield strength and bending strength reach the maximum values of 158. 60 MPa and 230. 40 MPa respectively at a sintering temperature of 1 150 ℃ and a sintering time of 180 min. [ABSTRACT FROM AUTHOR]

This study investigates the correlation between various micromagnetic signature patterns and the yield and tensile strengths of carbon steel (Cr12MoV steel as per Chinese standards). For this purpose, back-propagation neural network (BP-NN) models are established to quantitatively predict the yield and tensile strengths of carbon steels. The accuracy of prediction models is significantly affected by the presence of redundant micromagnetic signature patterns. By carefully screening the input parameters, it is able to effectively mitigate prediction errors arising from unreasonable model inputs. In the field of micromagnetic nondestructive testing (NDT), prediction models calibrated for a specific instrument or sensor cannot be directly applied to another instrument or sensor. In the study, a joint distribution adaptation transfer learning strategy based on auxiliary data is proposed to enhance the generalization of prediction models for cross-instrument applications. When auxiliary data accounts for 30% of the source domain data, the joint distribution adaptation transfer learning method based on auxiliary data improves the robustness of the model. The accuracy of the yield strength and tensile strength calibration models witnesses remarkable improvements of approximately 91.4% and 93.5%, respectively. [ABSTRACT FROM AUTHOR]

Mechanical properties including yield strength, hardness, and strain hardening are superior in additively manufactured H13 hot work tool steel (AMH) compared to conventional H13 (CMH), which are correlated with microstructural characteristics. Comprehensive microstructural analysis reveals that the strain is highly localized in the cell structure with retained austenite in AMH. Quenching and tempering (QT) heat treatment removes the cell structure and retains austenite from AMH, resulting in a microstructure and mechanical properties similar to CMH after QT. The constitutive equation for yield strength shows that retained austenite with sufficient amount of dislocation density in martensite contributes to higher yield strength in AMH than CMH and identical strengthening mechanism between AMH and CMH after QT. Furthermore, microstructural changes during plastic deformation are investigated to find the origin of high strain‐hardening rate in AMH. The relationship between hardness and indentation depth yields the higher statistically stored dislocation density in AMH than CMH. In addition to higher dislocation accumulation, transformation of retained austenite to α′ martensite results in transformation‐induced plasticity effect, which contributes to strain hardening. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive metallurgical analysis conducted on representative samples obtained from two batches of 17-4PH steel rods in order to investigate the underlying factors contributing to the observed differences in their mechanical properties. The samples underwent a solution annealing process followed by an aging treatment to achieve H1025 temper condition. Surprisingly, the mechanical properties of one batch namely 91/5 were found to be inferior compared to the other batch 91/7, with only the latter meeting the specified requirements. To gain a deeper understanding of these differences, a range of analytical techniques were employed. Local variation in austenite stabilizers and its corresponding effect on microstructure of batch 91/5 was found to be the root cause of lower mechanical property. [ABSTRACT FROM AUTHOR]

High-dimensional nonlinear relationships between the irradiated yield strength and its influencing factors, including doses, temperatures, and crystal structures, are difficult to explicitly characterize in the absence of a comprehensive database. In this study, we developed a machine learning method with the Fourier-transform-based feature extension, successfully constructing the prediction model of irradiated yield strength by a relatively small and sparse database of irradiated material properties. The analysis suggests that the proposed feature extension method improves the training performances of machine learning with small dataset. And the present model is accurate and feasible for predicting the irradiated yielding behaviors. Furthermore, we attempt the inverse machine learning model to determine material properties and irradiation conditions according to the desired yield strength. Since the parameter combinations commensurate with a fixed strength are diverse, the optimal model is helpful in reversely calculating and optimizing material performances. The data-driven machine learning method, which can detect the implicit correlations among numerous data, exhibits great prospects in investigating irradiated mechanical properties and exploring multiscale links in the nuclear material field. This work holds the promise for optimizing the design of in-pile structural components and can be further extended to other machine learning problems with the small dataset. [ABSTRACT FROM AUTHOR]

Aiming at ensuring the quality of the product and reducing the cost of steel manufacturing, an increasing number of studies have been developing nonlinear regression models for the prediction of the mechanical properties of steel rebars using machine learning techniques. Bearing this in mind, we revisit this problem by developing a design methodology that amalgamates two powerful concepts in parsimonious model building: (i) sparsity, in the sense that few support vectors are required for building the predictive model, and ( i i ) locality, in the sense that simpler models can be fitted to smaller data partitions. In this regard, two regression models based on the Least Squares Support Vector Regression (LSSVR) model are developed. The first one is an improved sparse version of the one introduced in a previous work. The second one is a novel local LSSVR-based regression model. The task of interest is the prediction of four output variables (the mechanical properties YS, UTS, UTS/YS, and PE) based on information about its chemical composition (12 variables) and the parameters of the heat treatment rolling (6 variables). The proposed LSSVR-based regression models are evaluated using real-world data collected from steel rebar manufacturing and compared with the global LSSVR model. The local sparse LSSVR approach was able to consistently outperform the standard single regression model approach in the task of interest, achieving improvements in the average  R 2  from previous studies: 5.04% for UTS, 5.19% for YS, 1.96% for UTS/YS, and 3.41% for PE. Furthermore, the sparsification of the dataset and the local modeling approach significantly reduce the number of SV operations on average, utilizing 34.0% of the total SVs available for UTS estimation, 44.0% for YS, 31.3% for UTS/YS, and 32.8% for PE. [ABSTRACT FROM AUTHOR]

The structure and mechanical properties of rolled sheets with a thickness of 40 mm made of low-carbon low-alloyed steel after thermomechanical treatment of different modes are investigated. The structural factors that affect obtaining high mechanical properties are established. It is shown that a complex treatment including quenching from the rolling temperature and high-temperature tempering with a subsequent additional cycle of quenching and tempering leads to formation of rolled sheet uniform over the cross section with a fragmented bainite structure with disperse niobium carbides and carbides of cementite type. Such structure provides a yield strength of no less than 630 MPa in combination with high values of the impact energy at negative temperatures and a level of plasticity of δ ≈ 20%. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract—This paper presents the effect of hot gas extrusion (HGE) parameters on the phase composition and mechanical properties of composite rods composed of a core with reaction products of a Ni–Al powder mixture and a steel shell at room temperature. Composite rods are produced in three HGE modes depending on the initial extrusion temperature and the gas pressure in the chamber with parent materials. The phase composition of the produced materials is studied. It is found that the extent of the reaction of the powder mixture increases at higher temperatures of the initial HGE and, accordingly, low gas pressures, but unreacted nickel and aluminum particles remain at the lowest temperature of the initial HGE (at a higher gas pressure). Three-point bending tests show that the yield strength of the composite rod whose core contains plastic inclusions of the parent nickel and aluminum is higher than the yield strength of the steel rod. The rods with the maximum extent of the reaction are observed to have the highest microhardness. [ABSTRACT FROM AUTHOR]

This research aims to identify an appropriate theoretical model for assessing the yield strength and elastic modulus of a composite material consisting of aerospace-grade aluminum 7075 base matrix reinforced with nanocrystalline high-entropy alloy particle (HEAp) composed of CrCuFeMnNi. To fabricate the aluminum composite with a high-entropy alloy base, an innovative casting method was utilized. This method involved the use of a modified bottom-pouring stir casting furnace, integrated with a mechanical supersonic vibrator and a squeeze infiltration setup. The measured theoretical density was higher than the actual density, while the cast specimen exhibited porosity below 6.6%. Scanning electron microscopy (SEM) images revealed the presence of strengthening precipitates and a uniform dispersion of HEAp in the composite. Comparing the developed HEAp composites (CH2, CH3, and CH4) with the base AA7075 cast CH1 (AA7075 + 0 wt.% CrCuFeMnNi-HEAp), the ultimate tensile strength increased by 4% for CH2 (5 wt.% CrCuFeMnNi-HEAp), 21% for CH3 (10 wt.% CrCuFeMnNi-HEAp), and decreased by 9% for CH4 (15 wt.% CrCuFeMnNi-HEAp). Similarly, the yield strength increased by 10% for CH2, 24% for CH3, and decreased by 5% for CH4. The elongation showed an increasing trend of 5% for CH2, 12% for CH3, and 2% for CH4. The flexural strength of the HEAp composites (CH2, CH3, and CH4) increased by 2%, 5%, and 10%, respectively. The proposed model yielded similar yield strength values that closely aligned and were consistent with the experimental value within a deviation of 3.32%. The modified Halpin-Tsai models agreed with experimental value up to a reinforcement volume fraction of 4.89% when calculating the elastic modulus. The proposed model and the Hashin-Shtrikman upper bound also agreed on values up to a 3.32% reinforcement volume fraction. [ABSTRACT FROM AUTHOR]

The effects of adding nickel on the phase transition temperature, microstructure, and mechanical properties of medium-carbon spring steel have been investigated. The results show that adding nickel reduces the martensite start (Ms) temperature, improves hardenability, and refines the sub-microstructure of the martensite, thereby improving yield stress. The yield strength of martensitic steel increases by approximately 100 MPa due to a synergistic combination of grain refinement strengthening and dislocation strengthening, with an increase in the nickel content from 0 wt.% to 1 wt.%. The cryogenic impact toughness of martensitic steel also improved with a higher nickel content due to packet and block refinement and an increase in the proportion of high-angle grain boundaries (HAGBs). [ABSTRACT FROM AUTHOR]