Steel Particles Research Articles

On the High Elastic Modulus Mechanism of Iron Matrix Composites

High modulus steels are characterized by high specific strength and specific stiffness, which can be attributed to the presence of hard reinforced particles. This paper investigates two common iron matrix composites, namely Fe/TiB2 and Fe/TiC, prepared through in situ reaction, focusing on their structures and properties. The results show that both types of reinforced particles in the high modulus steels consist of coarse primary particles and fine eutectic particles. In comparison to Fe/TiC composites, Fe/TiB2 composites exhibit larger elastic modulus (210 GPa). The reasons for the phenomenon that the experimentally measured values of the modulus of elasticity are lower than the calculated values at equilibrium are discussed. It was found that microporous defects left over from the casting process are often present inside the coarse primary particles, which can be the source of microcracks or fractures. In addition, matrix/particle interface stability calculations revealed that TiB2 possesses a distinctive hexagonal structure, resulting in a smaller interfacial distance (d0 = 1.375 Å) with the ferrite matrix phase. The high interfacial work of adhesion (Wad = 3.992 J/m2) further confirms the stronger interfacial stability of the Fe/TiB2 composite in comparison to the Fe/TiC composite.

Microstructure and Nanomechanical Properties of Heat Treated AlCu Composites Reinforced with SiC and Stainless Steel Particles

Microstructure and Nanomechanical Properties of Heat Treated AlCu Composites Reinforced with SiC and Stainless Steel Particles

Characterization of Particle Fluidization in a New Type of Fluidized Bed Flotation Unit

ABSTRACTUnderstanding the hydrodynamics of the bed layer in a fluidized bed is essential for optimizing and improving fluidized bed flotation units. This study proposes a fluidized bed flotation column that incorporates auxiliary particles into the gas–liquid two‐phase system to address the shortcomings of traditional flotation units. Stainless steel particles (glass beads), tap water, and compressed air were used as the solid, liquid, and gas phases, respectively. Key factors affecting the bed hydrodynamics (such as bed fluctuation, minimum fluidization velocity, bed expansion, and porosity) in the fluidized column include gas and liquid flow rates as well as the initial bed height. Experimental results show that selecting appropriate filling particles can effectively enhance the fluidization performance of the bed, while appropriately increasing the gas flow rate can achieve fluidization at lower liquid velocities, thus reducing energy consumption during the flotation mineralization process. Theoretical analysis combined with extensive data reveals that the expansion characteristics of the fluidized bed and the use of high‐density filling particles can effectively mitigate bed layer fluctuations and stabilize the flow field environment. Additionally, based on a wide range of data, this study employs model factor analysis, dimensionless analysis, and multiple linear regression analysis to propose a standard dimensionless parameter model for the fluidized bed flotation column, which can effectively predict bed layer fluctuations and expansion characteristics.

Skin absorption of metals derived from hydrogenated stainless particles in human skin: Results from the TITANS project

Workers involved in the decommissioning and removal of radioactive material from nuclear power plants can come into contact with tritiated dust from stainless steel. This study aimed to investigate metal penetration and permeation after skin contamination with these particles.Static diffusion Franz cells were used with intact, damaged, or broken human skin. Stainless steel particles 316 L were applied to the donor phases, and the receiving solutions were collected at regular intervals for 24 h to determine the amount of metals that penetrated the skin. The effectiveness of the decontamination procedure was investigated after 30 min using water and soap. The metal content in the skin was evaluated after 24 h of exposure. Metals detected were Ni, Cr, Co, Mn, Cu, Mo.For Ni, Mn, and Cu, we found a significant increase in metal permeation in all treated cells compared with the blank (p < 0.02). For Co and Cr, permeation through the skin was significant only in the decontaminated and broken cells (p < 0.05). Decontaminated skin presented higher metal permeation for Ni, Co and Cu compared to intact skin (p < 0.05) while broken skin presented, as expected, the higher permeation profile (p < 0.05) for all metals. The metal that was more represented inside the skin was Cr, with more than 15 μg/cm2 for intact skin. Ni inside the skin reached the 10.2 ± 8.5 μg/cm2 for intact skin.Overall, the levels of metals in the receiving solution were very low in the case of intact and damaged skin contact, and the metal levels significantly increased only in the case of broken and decontaminated skin.More relevant appears Skin content with sensitizing metals (Ni, Cr, and Co) that can induce allergic sensitization or cause allergic contact dermatitis in subjects already sensitized.

On Thermoelastic Impact Modelling of Frozen Composite Target During Pre – Heated Projectile Penetration Starts of Motion

This study investigates a composite double-layer structure for improved thermal shock resistance. A modified Hugoniot elastic limit model is presented for the composite, followed by a 2D thermo-elastic impact simulation using commercial software. The simulation focuses on a composite material under initial extreme low temperature conditions with alternating metallic (Steel, Aluminum) and non-metallic layers (Kevlar 49, Graphite). The frozen target is subjected to pre- heated projectile. The objective is to optimize the composite's durability by strategically placing reinforcement particles within specific layers. The analysis explores the effect of different particle types (oil, water, Aluminum, Steel) and sizes (0.3mm, 0.5mm, 1mm) on the composite's stress response. It was found that aluminum and steel particles significantly reduce stress compared to fluid/gas particles, confirmed qualitatively by literature. Kevlar particles within the SiCp layer enhance its resistance, while Aluminum particles within the Kevlar layer offer weight reduction benefits. Moreover, for Kevlar, larger particles improve resistance, and vice versa for the SiCp case. Considering weight, a particle size of 0.5mm is chosen for both layers. Moreover, a finite element analysis of the optimized composite model subjected to thermoelastic impact loading demonstrates its superior performance compared to the non-reinforced composite. Specific layer combinations (SiCp with Kevlar particles, Graphite or Kevlar with Aluminum particles) show the most significant stress reduction. Finally, separate 3D ballistic analysis was performed for Tungsten having 600m/sec projectile into 5 layered target with thickness of 2.8mm each layer and appropriate interaction friction (SiCp - Steel 304 - Al 7075-T651 - Kevlar 49 - Graphite Crystalline) during penetration time of 0.006sec at 300K. The dynamic explicit transient analysis was confirmed with the predecessors' analytic calculations.

Stochastic approach to evaluate the shielding effectiveness of composite materials loaded with randomly oriented helices

AbstractThis letter proposes a method to calculate the expected value of the shielding effectiveness of a composite material slab, including a planar array of randomly oriented metal helices as chiral particles. Helix‐loaded concrete composite materials are advantageous for electromagnetic interference shielding applications. While planar periodic arrays of chiral particles have been extensively studied, this research discusses a non‐periodic array in which the helical particle axis direction in each unit cell is random. This method estimates the slab's shielding effectiveness by defining it as a random variable expanded into three independent basis‐like functions. Comparisons with full‐wave simulations show acceptable agreement across a wide frequency range, with a total RMS error of 0.9 dB. This study additionally includes an experimental measurement to validate the proposed method. This technique provides the initial step in developing an analytical method to analyse and estimate the transmitted power of general structures using a stochastic approach. Examples include concrete composites containing randomly distributed helical steel particles with significant shielding effectiveness.

Numerical investigations of heat transfer and pressure drop in packed bed duct exposed to forced convection boundaries under local thermal non-equilibrium conditions

The present study is a 2-D numerical study which discusses the thermohydraulic performance of packed bed duct under local thermal non-equilibrium and steady state conditions exposed to forced convection boundaries (BC-6). The numerical model is well validated with the experimental work reported in the literature and found to be accurate enough to perform further parametric investigations. The analysis is done to see the effect of different ball diameter (5 mm, 9 mm and 11 mm), bed porosity, heat transfer fluid (air, water and engine oil - Pr = 0.70–645) and ball material (EPS, steel and bronze) on heat transfer and fluid flow characteristics in turbulent flow region of Reynolds number ranging from 900 to 14,320. The numerical results obtained using commercial CFD software COMSOL shows that, the heat transfer coefficient and pressure drop in packed bed increases with increase in ball diameter, thermal conductivity of ball and bed porosity which is exactly reverse as reported in literature for BC-1 to BC-5. The maximum thermal performance factor with bronze particles is 2.45 and 24.5 times more than stainless steel and EPS particles respectively for larger particle size and bed porosity. Engine oil exhibits significantly higher heat transfer coefficient (9.7 × 105 W/m2K) and pressure drop (3.3 × 106 Pa) compared to water (40,126 W/m2K and 2028 Pa) and air (600 W/m2K and 250 Pa) respectively. Overall, the combination of water as heat transfer fluid along with bronze particles of larger diameter and larger bed porosity emerges as the optimal choice for enhancing heat transfer in the packed duct exposed to forced convection boundary condition BC-6.

Rapid carburizing of low-alloy steel by atmospheric-controlled induction-heating fine-particle peening and investigation of its fatigue properties

Atmospheric-controlled induction-heating fine-particle peening (AIH-FPP) was applied to low-alloy, low-carbon steel AISI 4120 to achieve rapid carburizing within minutes and enhance fatigue strength. The shot particles used during AIH-FPP were specifically created by mechanically milling a mixture of steel particles and carbon powders. The specimens were analyzed using laser microscopy, optical microscopy, X-ray diffraction for residual stress measurement, a micro-Vickers hardness tester, and an electron probe micro-analyzer. Axial fatigue tests and fracture surface analyses via scanning electron microscopy and energy-dispersive X-ray spectroscopy were also conducted. AIH-FPP effectively transferred carbon to the treated surface and facilitated its diffusion in a short period, creating a martensite layer with high hardness and compressive residual stress, which resulted in increased fatigue strength. The fatigue strength of the AIH-FPP-treated specimens was influenced by the conditions of reheating and quenching, which altered the prior austenitic grain size and stress concentration at the specimen surface. Notably, specimens treated with AIH-FPP followed by reheating and water-injection quenching exhibited fatigue strength comparable to that of conventional gas-carburized specimens, owing to the formation of a carburized layer with a small prior austenite grain size.

Microstructure Refinement via Nucleation of Intragranular Acicular Ferrite Stimulated by Ti-Containing Core-Shell Structured Particles in Low-Carbon Steel.

This study investigated the microstructure, mechanical properties, and nucleation mechanism of acicular ferrite (AF) present in hot-rolled Ti deoxidized steel. In our experiments, the impact toughness of Ti deoxidized steel is significantly increased to 144 J at -20 °C, while those Mn and Al deoxidized steels are only 9 J and 18 J, respectively. Interlocked AF is the primary microstructure of Ti deoxidized steel. The second-phase particles of the core-shell-type structure, in which Ti2O3 is the nucleus and TiO is the outermost shell, act as effective nucleating agents to stimulate AF nucleation. The low lattice disregistry between TiO and AF is the main factor contributing to the production of AF. It is also revealed that Ti2O3 and MnS fulfill the particular orientation relationship, contributing to the formation of an Mn-depleted zone (MDZ) adjacent to MnS, proposed to be one of the possible mechanisms for promoting AF nucleation.

Spotting ignition of plastic foam by a fast-moving hot metal particle

Spotting ignition involves dynamic interaction between fuel bed and hot particles, but the scientific understanding of the ignition by a fast-moving hot particle is still limited. Herein, a hot steel particle with various horizontal velocities, temperatures, and sizes is shot to ignite vertically oriented low-density expandable polystyrene foam. A high-speed particle can directly get embedded into the foam to achieve flash-point, fire-point, or no ignition, while a low-speed particle bounces away from the foam without ignition. Results show that for a particle of 1150 °C, its minimum velocity for embedding is 12.00 m/s. Such a critical velocity for hot-particle embedded or ignition slightly decreases as particle temperature increases. Minimum ignition temperature of these high-speed particles is 200 °C higher than that of near-static or with a low free-fall velocity, due to the shorter residence time and insufficient to produce a flammable mixture. Moreover, when the particle is neither too slow to bounce away nor too fast to get embedded, it will be partially embedded on the sample surface to burnout the fuel, posing the biggest fire hazard. It deepens our knowledge of the complex interaction between hot moving particles and insulation foam to reduce spotting fire risk for building façade.

Exploring the efficiency of powder reusing as a sustainable approach for powder bed additive manufacturing of 316L stainless steel

The efficiency and sustainability of Laser Powder Bed Fusion (L-PBF) greatly depends on the ability to recycle the used powder since a large portion of the feedstock remains unsolidified surrounding the printed part. To assess the impact of reusing iterations on the properties of the feedstock and printed part, we employed thermodynamic simulation to study oxidation in the building chamber. We then compared the 5 times reused powder of austenitic steel 316L (SS316L) and the printed part with its virgin counterpart. Our findings revealed that minor residual oxygen in the building atmosphere reacts with the molten pool and hot spatters, leading to the formation of Rhodonite (MnSiO3) inclusions. As sieving cannot remove oxides smaller than steel particles, the repetition of feeding the used powder into the printing process directly increases the fraction of oxides in the printed parts. The increase in inoculated oxygen by reusing, coupled with the dissolution of oxides into the molten pool, facilitates the formation of Spinel (MnCr2O4) and Tridymite (SiO2) oxides, as well as clustered inclusions. While small oxides anchor cellular structures, stress concentration on the coarse fragile inclusions leads to sudden rupture and weaker tensile strength of the printed part with reused SS316L powder.

Welding load, temperature, and material flow in ultrasonic vibration enhanced friction stir lap welding of aluminum alloy to steel

To elucidate the effect of ultrasonic vibration on the welding process (welding load, thermal cycle, and material flow) of aluminum/steel dissimilar metals in friction stir lap welding, conventional friction stir lap welding (FSLW) and ultrasonic vibration enhanced friction stir lap welding (U-FSLW) were used to weld aluminum/steel dissimilar metals. The results indicate that applying ultrasonic vibration to the FSLW of aluminum/steel dissimilar metals can effectively decrease welding loads (tool torque, axial force, and spindle power), and it was found that the reduction in welding load was inversely proportional to the welding speed. The effect of additional ultrasonic vibration on axial force was the largest. Ultrasonic vibration had a significant preheating effect, and its thermal effect in the width and depth directions of the workpiece gradually weakened. Additional ultrasound can reduce the peak temperature during the welding process. The instantaneous state of the weld was obtained using the "emergency stop+emergency cooling" technology, and the three-dimensional visualization characterization of material flow near the keyhole was achieved using X-ray based computer tomography (CT). It was found that ultrasonic vibration could increase the material's plastic flow, change the steel structure's flow path, and significantly increase the steel particles' flow range near the pin tool. Compared with conventional FSLW, the changes in the macro/microstructure of U-FSLW joints were closely related to the welding thermal cycle and material flow.

Solid-state aluminizing process for high-adhesion composite coatings: Synergistic effects of plastic flow, atomic mixing and interaction on structure and properties

This study introduces a solid-state aluminizing technique through a vibratory milling process, employing a distinct combination of milling balls to fabricate Al composite coatings with high adhesion on steel substrates. The process is carried out at ambient temperature, without the need for special atmospheric conditions. The process utilizes the synergistic effects of plastic flow, atomic mixing, and interatomic interactions to produce coatings with outstanding mechanical properties, and corrosion resistance, challenging to achieve through conventional methods. The as-fabricated composite coating consists of W, Ni, and steel particles, constituting 7–10 % of the composition, dispersed within an Al matrix with an average grain size of approximately 50 nm. The Al coatings demonstrated a hardness threefold greater than untreated steel and fivefold higher than the initial Al balls used for deposition, alongside an exceptional 20 % elastic recovery. Moreover, the aluminized steel exhibited a corrosion rate more than five times lower than untreated steel, underscoring the coatings' dual enhancement of mechanical strength and corrosion resistance.

Ship base vibration reduction design technology based on visualization of power flow and discrete optimization

The ship base is a structure that connects the equipment to the hull and may play a role in restraining and isolating the dynamic load. Adding damping on the base to improve the vibration isolation performance is an important measure to control ship vibration. In this research, the energy transfer route and vector cloud of the ship base were analyzed employing the power flow theory, and then the placement of the particle damper was determined. Through the discrete optimization of different particle parameters including the particle material, diameter and filling rate, the best vibration reduction effect was acquired. The simulation and experiment results show that the particle damping has obvious damping effect, and the steel particle has better damping effect than the lead particle and the aluminum particle. The change of particle filling rate influences the vibration characteristics, and the best effect is achieved when the filling rate is 82%. The vibration reduction performance relies strongly on particle diameters, and they all exert obvious vibration suppression effect at the peak acceleration admittance. The proposed discrete optimization strategy effectively saves experiment cost, and the presented particle damper may be traded as an optional scheme in vibration reduce treatment of ship base.

Oxide particles in oxide dispersion strengthened steel neutron-irradiated up to 158 dpa at Joyo

We investigated the stability of oxide nano particles in oxide dispersion-strengthened (ODS) steel, which is a promising candidate material for next-generation reactors, under neutron irradiation at high temperature to high doses. MA957, a 14Cr-ODS steel, was irradiated with Joyo in Japan Atomic Energy Agency under irradiation conditions of 130 dpa at 502 ºC, 154 dpa at 589 ºC, and 158 dpa at 709 ºC. Three-dimensional atom probe (3D-AP) and transmission electron microscope (TEM) observation were performed to characterize the oxide particles in the ODS steels. A high number density of Y-Ti-O particle was observed in the unirradiated and irradiated samples. Almost no change in the morphology of the oxide particles, i.e. average diameter, number density, and chemical composition, has been observed in the samples irradiated to 130 dpa at 502 ºC and to 154 dpa at 589 ºC. A slight decrease in number density was observed in the sample irradiated to 158 dpa at 709 ºC. The hardness of any of the irradiated samples was almost unchanged from that of the unirradiated sample. It was revealed that the oxide particles existed stable, and the strength of the material was sufficiently maintained even after being neutron irradiated to high dose of ∼160 dpa at high temperature up to 700 ºC.

Axial compressive performance of thin-walled square steel tube concrete short column with built-in steel slag block

In the process of iron and steel production, steel slag is produced as waste. The steel slag processing method generally produces steel slag cement as a substitute for gravel and fine aggregates. Steel slag aggregates replace natural aggregate concrete used in concrete components. In addition, steel slag expansion can compensate for the shrinkage characteristics of concrete and steel pipes inside closed wet environments, and the outer steel tube hoop constraint can avoid late hydration expansion structure cracking. Through orthogonal testing, the wall thickness of the steel pipe (3 mm, 3.75 mm, 4.5 mm), content of the steel slag blocks (10 %, 15 %, 20 %) and particle size of the steel slag blocks (40–60 mm, 60–80 mm) were used as experimental variables to conduct axial compression tests on 9 groups of short columns made of slag aggregate concrete-filled thin-walled square steel tubes. Based on the analysis of the test process and displacement, strain, ductility and ultimate bearing capacity results, the failure pattern and mechanism of the short column specimens under axial compression were obtained, and a bearing capacity calculation formula was obtained according to the existing theoretical methods. The results indicate three failure patterns: local convexity, shearing and circumferential bulging. The factors influencing the bearing capacity, from most influential to least influential, are the particle size of the steel slag, the wall thickness of the steel pipe and the amount of steel slag. The Poisson's ratio of core concrete has an important effect on its passive binding force, which affects the longitudinal displacement and load-bearing capacity of the component. The deduced formula can be used to accurately calculate the ultimate bearing capacity of the square steel tube and steel slag concrete. This article transforms the drawbacks of steel slag concrete into advantages and, by combining the characteristics of steel tube concrete, proposes a new type of composite component that has a certain degree of innovation and application value.

Employing Metal-Enriched Polymeric Composites: An Innovative Approach for Combatting Microbes and Bacteria in Building Components in Public Places

The escalating occurrence of hospital-associated infections globally, compounded by the ongoing pandemic, has spurred researchers to delve into innovative approaches for combating pathogens and overcoming their resistance to commonly used materials. One of the most important concerns is frequently touched building components in public places and hospitals, which serve as potential sources of infection transmission, prompting a pressing need for effective antimicrobial solutions. This research developed antimicrobial polymeric composites comprising Copper (Cu), Aluminum (Al), and Stainless Steel (SS) particles incorporated into Polylactic Acid (PLA) via injection molding as a commercial method for the production of building components, to investigate the antimicrobial properties. The study aims at increasing the antimicrobial efficiency of polymeric composites with different metallic particles and tests the prepared polymeric composites (two sets of Cu-enriched composites, i.e., Cu–PLA–SS, by mixing Al–PLA with Cu–PLA, and Cu–PLA–Al, by mixing SS–PLA with Cu–PLA) against various bacteria. The results demonstrate that the samples prepared with Cu-PLA mixed with SS and Al exhibited the best antibacterial activity (98.6%) after 20 min of exposure to all bacteria, notably against Staphylococcus aureus and Enterococci. In addition, the hybrid composites Cu–PLA–SS and Cu–PLA–Al, prepared using injection molding, showed similar antimicrobial activity against all bacteria compared to those prepared using 3D printing. Therefore, polymeric composites enriched with metallic particles such as Cu, Al, and SS prepared via injection molding show potential in biomedical applications, food packaging, tissue engineering, and various technological industries, offering viable solutions for environments where risks from contact with infected surfaces are a concern.

Interfacial structure and formation mechanism of 90 W-7Ni-3Fe/steel using co-sintering method

In this study, we proposed a powder metallurgy method to develop an interlocking interface in tungsten heavy alloy/steel composites, which is achieved by co-sintering technology using tungsten heavy alloy and steel powders with a large difference in particle size. The interfacial microstructure evolution and mechanical properties of the co-sintered joint as a function of co-sintering temperature were investigated systematically. Results showed that a well-bonded interlocking interface was formed along the steel particles as a result of the tungsten heavy alloy particles filling in the gaps between two neighboring steel particles. The co-sintered joint contains four regions: the W alloy matrix, the Fe3W3C layer, the Ni-affected layer, and the steel matrix. Based on the microstructural characterization, the interface formation mechanism and reaction layer growth behavior are discussed in depth. Benefitting from the interlocking structure, the highest tensile strength of the co-sintered specimen is 265 MPa, which is 66% higher than that of the non-interlayer joint obtained by diffusion bonding method. Moreover, its performance is better than that of some W alloy/steel with an interlayer. This technique offers a potential method for the efficient preparation of a W alloy/steel composite structure with outstanding properties.

Fused filament fabrication using stainless steel 316L‐polymer blend: Analysis and optimization for green density and surface roughness

AbstractThis study is centered on the analysis of composite component additive manufacturing, via fused filament fabrication (FFF), comprising of 316L stainless steel particles in a polymer matrix. It examines the impact of several process factors of FFF, including extrusion speed, layer height, and extrusion temperature, on the density and surface roughness with the goal to minimize porosity. The independent and interaction impacts of these parameters were investigated using a central composite design technique. The technique of analysis of variance was utilized to determine the influence of relevant factors. Regression analysis was used to establish statistical models linking the parameters to green density and surface roughness. The green density was enhanced by reducing the layer height from 0.2 to 0.1 μm and decreasing the nozzle speed from 100 to 20 mm min−1. The surface roughness was improved by using a slow printing speed and minimum layer height. The ideal temperature range for producing favorable results in terms of green density and surface roughness during extrusion was found to be between 235 and 240°C. Significant correlations were found between the parameters and the green density and surface roughness. A genetic algorithm was used as an optimisation tool to determine the thresholds that would provide the highest green density and the lowest surface roughness values. The porosity of the samples generated with the optimized settings was evaluated using microtomography scans. The methodology presented here can be applied to composite and standard polymeric filament printing to determine optimal printing parameters.Highlights Blend of stainless steel 316L and polymer was used for fused filament fabrication. Printing speed and layer height were the dominating for density and roughness. Height 0.2 mm, speed 20 mm s−1, and temperature 239°C resulted 4.73 g cm−3 density and 21.09 μm roughness Microtomography revealed porosity of 1.7% in the optimized sample.

Tailoring metal powders by dry nanoparticle coating for powder bed fusion applications

The influence of high intensity mixing of graphene platelets with stainless steel particles in the scope of additive manufacturing is investigated. Therefore, 0.75 vol% graphene platelets were coated onto conventional stainless steel powder as a model material, resulting in very homogenously distributed graphene layers. The specific energy input during mixing was found to be the main factor for increasing the flowability and decreasing the reflectivity of the powder. Furthermore, the resulting surface roughness of the coated powders could be correlated with a theoretical consideration of van der Waals forces. In this way, the mixing process can be controlled regarding its specific energy input to achieve tailored powders for the application in PBF-LB/M. Cubic parts were produced with different laser parameters and analysed. As a result, the admixing of graphene at lower specific energies resulted in a wider process window and parts with a relative density of 99.99% were achieved.