Modulus Steel Research Articles

Effects of TiB2 particles on deformation behavior, softening mechanisms and recrystallization texture of hot-compressed Fe-TiB2 composites

Fe-TiB2 composites, also termed as high modulus steel, offer a promising solution to the challenge of achieving both lightweight and high stiffness materials. However, the presence of TiB2 particles in Fe-TiB2 composites results in poor hot-workability. Therefore, understanding the effects of TiB2 particles on the hot deformation behavior, dynamic recrystallization (DRX), and microstructural evolution of Fe-TiB2 composites is crucial for optimizing their hot-working process. In this study, we elucidated the effects of TiB2 particles on deformation behavior and dynamic softening behavior by conducting a series of isothermal compression tests on as-cast Fe-TiB2 composites and as-cast base alloys (control group) at temperatures of 800–1200 °C, strains of 0.36–1.2, and strain rates of 0.01–1 s⁻1. Using electron backscatter diffraction, we characterized the microstructures of composites and base alloys, showing that TiB2 particles induce a DRX process through particle stimulated nucleation (PSN) at low temperatures and promote continuous dynamic recrystallization (CDRX) at high temperatures. The presence of TiB2 particles have significantly affected the dislocation movement and distribution, which changes the deformation energy distribution and thus facilitates different DRX behaviors under various thermal deformation conditions. Additionally, the microstructure resulting from DRX through PSN exhibits significant texture weakening and grain refinement, presenting a promising method for fabricating ultrafine-grained Fe-TiB2 composites.

Milling of TiBbm2 Particle Reinforced High-Modulus Steel

TiB2 particle reinforced high-stiffness steel is one of the composite materials that aim to improve Young’s modulus by compositing TiB2 particles into a stainless steel base phase. This material is designed to exhibit higher rigidity and strength than conventional iron-based materials by using TiB2 particles as the reinforcing phase, and is expected to reduce the weight of high-load components in engines. For this reason, tool life is very short when machining this material. Therefore, high Young’s modulus steel containing TiB2 particles is known to be one of the most difficult-to-cut materials. The purpose of this study was to investigate how to extend tool life in the milling of high-Young’s-modulus steel. Cutting speed dependence of tool life was investigated by end milling using a binderless CBN tool with excellent hardness and bending strength. In addition, the tool damage mechanism was also investigated. The results showed that tools composed of binderless CBN tool have a longer life than conventional CBN tool. In this type of binderless CBN tool, the tool wear rate tended to increase with increasing cutting speed. In addition, the longest tool life was obtained at a cutting speed of 1.25 m/s, though wear rate increased at a boundary cutting length of 1300 m. The wear rate was found to increase with increasing cutting speed. Temperature measurement results indicate that the primary cause of tool damage was mechanical wear, as the temperatures were much too low for a reaction between cBN and Fe. Friction tests revealed scratch marks on the tool originating from crushed cBN particles produced by the crushing of the cutting edge. This indicates that wear is accelerated by the high frictional energy of the cBN powder rubbing against the flank face.

Effect of substrate temperature on in-situ precipitation during laser powder bed fusion of Fe-TiB2 high modulus steel

ABSTRACT Fe-Ti-B high modulus steel (HMS) fabricated via laser powder bed fusion exhibits in-situ precipitation of nanostructured TiB2 particles within a ferritic Fe-matrix. However, porosity and cracking are common challenges associated with this process. This study systematically varies process parameters, specifically volume energy density and substrate temperature, to analyse macroscopic defects formation and propose methods to prevent their occurrence through detailed microstructure characterisation. For substrate temperatures of 400, 600, and 800 °C, an optimal combination of laser power and scan velocity was determined, resulting in minimised specimen porosity (< 1%). Yet, pronounced cracking occurred at 400 and 600 °C substrate temperature, most likely attributed to the presence of hard and brittle non-equilibrium microstructure constituents. Increasing the substrate temperature to 800 °C further reduces porosity and promotes the formation of the equilibrium constituents Fe-α and TiB2. These phases are desirable as they improve the stiffness-to-density ratio while reducing hardness and brittleness. By mitigating thermal gradient and resulting lower stresses, the successful fabrication of HMS samples with the desired microstructure and defect-free macrostructures becomes feasible. Potential future steps, such as incorporating in-situ heat treatments between layer depositions, are outlined and discussed as means to lower the substrate preheating temperature.

The Microstructure Evolution during Divorced Eutectoid Transformation in a κ-Carbide Reinforced High Specific Young’s Modulus Steel

High specific Young’s modulus steel reinforced by κ-carbides has the characteristics of high strength and low density, which introduces potential applications of this material in automotive parts with a stiffness requirement. In this work, a 780 MPa grade Fe-Al-C high specific Young’s modulus steel was developed, and the addition of high contents of carbon and aluminum introduced a large fraction of κ-carbides into the steel matrix. To improve the ductility of this steel, a divorced eutectoid transformation (DET) treatment was adopted to regulate the microstructure of κ-carbides. A detailed evolution of κ-carbide during DET was investigated by staged quenching and microstructure characterization. It has been found for the first time that the κ-pearlite transformation and κ-carbides precipitation were mainly completed in the early stage during slow cooling, and the spheroidization of κ-carbides was mainly completed in the later stage. In addition, the effect of DET parameters on the microstructure evolution was analyzed, and it was found that a better spheroidization effect of carbides can be obtained at a lower cooling rate.

Feasibility of using contactless electromagnetic cavitation for steel composite manufacturing

This work investigates the feasibility of using contactless electromagnetic sonication for dispersing and refining the strengthening phase in iron and steel for ferrous metal matrix composite production. An oscillating pressure field is generated under superimposed alternating (0.13 T) and steady magnetic fields (up to 8 T). The processing employs a static floating-zone technique and is crucible-free. This approach allows to reach an around 0.8 MPa pressure oscillation amplitude that is sufficient to initiate acoustic cavitation in high melting temperature liquid metals. The viability of different reinforcement dispersions, both ex situ and in situ using this electromagnetic sonication, is explored in the context of the production of oxide dispersion strengthened steel and high modulus steel. Figs 3, Refs 9.

High Modulus Steel Produced by Cold Spray Additive Manufacturing

High Modulus Steel Produced by Cold Spray Additive Manufacturing

Nanoparticle enabled high performance high modulus steels

Here we present a novel concept that uses a low volume fraction of nanoparticles to nano-treat Fe-Ti-B melts for a new high performance high modulus steel (HMS). Microstructures of the nano-treated Fe-Ti-B HMS were investigated. The nano-treated HMS consists of fine TiB2 particles and a strengthening phase of unexpected ultrafine Fe2B lamellas. While Fe2B phase is traditionally considered to be detrimental in steel making due to its inherent embrittlement effect, this study shows a successful conversion of the detrimental Fe2B phase into an advantageous one. The nano-treated HMS has significantly higher tensile strength compared to its conventionally made counterpart, 950 MPa vs. 510 MPa, while retaining the high Young's modulus, low density, and ductility. This new concept effectively demonstrates the successful structural refinement in Fe-Ti-B system using nanoparticles, without changing the solidification rate, which eliminates the dilemma between achieving enhanced mechanical properties versus manufacturing for mainstream applications and enables the use of stiff HMS for lightweighting of practical applications. A new mechanism of nanoparticle-induced solute enrichment at nanoscale in alloy melts was also proposed and has implications for new manufacturing routes of metals.

Flexural Behaviour of Hybrid Fibre Reinforced Concrete Beam by using (LC3) Cement

In this paper, the flexural behavior of hybrid fibre reinforced concrete beams was investigated. Two types of hybrid fibres were used. used in this study, one is having high young’s modulus steel fibre (Hooked end) and another one is having low young’s modulus Polypropylene fibre with different proportions. Nine types of reinforced concrete beams were made by using M50 grade high strength concrete mix a volume factors of hybrid fibres as 1.5%. this beams includes conventional concrete, LC3 concrete and he beam with the following combinations of hybrid fibres such as OPC 100%, LC3 100%, SF100%, SF25% -PF75%, SF40%-PF60%, SF50%-PF50%, SF60%-PF40%, SF75%-PF25%, PF100%, the working results shows that percentage proportion of combined SF-PF at 75%-25% had the best implementation on its flexural strength. Experimental results also shows that beam with SF75%-PF25% had their structural stiffness, ductility index and energy absorption capacity have been improved the most as compared with the conventional concrete and other fibre combinations of beams.

Flexural Performance of Hybrid Engineered Cementitious Composite Layered Reinforced Concrete Beams

This paper presents the experimental investigation to evaluate the flexural performance of newly developed hybrid Engineered Cementitious Composite (ECC) layer at tension zone around the main reinforcement of beam. Four different ECC mixes are used in the beam to evaluate the flexural performance, hybrid ECC based on the low modulus poly vinyl alcohol (PVA) and high modulus steel short random fibre reinforcement. The aim of hybridation is to improve the flexural, energy absorption and ductility performance of reinforced concrete beams. In addition to the compressive strength, young’s modulus, uniaxial tensile strength and bond strength of ECC mixes are determined. ECC with PVA fibre with 2.0% volume fraction mix is kept as reference mix, hybridation is made with PVA (1.35%) and steel (0.65%), PVA (1.00%) and steel (1.00%) and finally with PVA (0.65%) and steel (1.35%). This hybridization has a remarkable achievement in mechanical properties and in the flexural behavior in ECC layered RC beam. From the results, it has been observed that mono fiber ECC reinforced with PVA of 2.0% and hybrid fiber ECC reinforced with 1.35 % of PVA fiber and 0.65% of steel fiber has reasonable flexural characteristics than the conventional beam.

Stiff, light, strong and ductile: nano-structured High Modulus Steel

Structural material development for lightweight applications aims at improving the key parameters strength, stiffness and ductility at low density, but these properties are typically mutually exclusive. Here we present how we overcome this trade-off with a new class of nano-structured steel – TiB2 composites synthesised in-situ via bulk metallurgical spray-forming. Owing to the nano-sized dispersion of the TiB2 particles of extreme stiffness and low density – obtained by the in-situ formation with rapid solidification kinetics – the new material has the mechanical performance of advanced high strength steels, and a 25% higher stiffness/density ratio than any of the currently used high strength steels, aluminium, magnesium and titanium alloys. This renders this High Modulus Steel the first density-reduced, high stiffness, high strength and yet ductile material which can be produced on an industrial scale. Also ideally suited for 3D printing technology, this material addresses all key requirements for high performance and cost effective lightweight design.

Ceramic reinforced high modulus steel composites: processing, microstructure and properties

Ceramic reinforced steel matrix composites are materials for automotive, aerospace, wear and cutting applications. Such metal matrix composites (MMCs) combine attractive physical, mechanical and wear properties with ease of fabrication and low cost. The review focuses on the current state of the art of producing these metal matrix composites, ceramics reinforcements, composition of steel matrix, microstructure evolution and parameters influencing the mechanical and wear properties. Processing methods to fabricate ceramic reinforced steel matrix composites are discussed to produce these composites with low number of defects, homogeneous microstructure and high mechanical and wear performance. The influence of chemical nature of ceramic reinforcements and composition of steel matrix on the microstructure, mechanical and wear properties is presented. The strengthening mechanisms and parameters controlling wear performance of steel MMCs are described as a function of the content of ceramic reinforcements, microstructural design and structure of the steel matrix. Keeping in view the stability of ceramics in steels, suitable ceramic reinforcements and steel matrix materials are discussed. Moreover, the importance of microstructure and interface between ceramic reinforcement and steel matrix in controlling the mechanical properties of steel MMCs is highlighted. The review identifies area of research for development to fully appreciate and tailor the properties of these industrially important composites.Les matériaux composites à matrice d’acier, renforcés de céramique, sont des matériaux pour application dans l’industrie automobile, aérospatiale, de l’usure et du découpage. Les matériaux composites à matrice métallique (MMCs) en acier et céramique combinent des propriétés attrayantes physiques, mécaniques et d’usure, à la facilité de fabrication et au coût faible. Cette revue se concentre sur l’état de la technique courante de production des matériaux composites à matrice d’acier, renforcés de céramique, sur les renforcements en céramique, sur la composition de la matrice d’acier, sur l’évolution de la microstructure, sur les propriétés mécaniques et sur les paramètres importants qui contrôlent les propriétés mécaniques et d’usure. On discute des méthodes de traitement pour la fabrication des matériaux composites à matrice d’acier, renforcés de céramique afin de produire des MMCs avec peu de défauts, une microstructure homogène et un rendement élevé des propriétés mécaniques et d’usure. On décrit l’influence de la nature chimique des renforcements et de la composition de la matrice en acier sur le développement de la microstructure et sur les propriétés mécaniques et d’usure. On décrit les mécanismes de renforcement et les paramètres contrôlant le rendement à l’usure des MMCs en acier en fonction de la teneur en renforcement de céramique, de la conception de la microstructure et de la structure de la matrice en acier. Gardant en vue la stabilité des céramiques dans les aciers, on discute des matériaux appropriés de renforcements céramiques et de matrice d’acier. De plus, on souligne l’importance de la conception de la microstructure et de l’interface dans le contrôle des propriétés mécaniques des MMCs en acier. Cette revue identifie des sujets de recherche à développer afin de comprendre complètement et de créer sur mesure les propriétés de ces matériaux composites d’importance industrielle.

Evaluation of Bonding between High Modulus CFRP Sheet and Steel after Environmental Exposure and Fatigue Loading

This study investigated the effects of fatigue loading and corrosive environment on bonding strength and failure modes of Carbon Fibre Reinforced Polymer (CFRP)-laminated steel. A series of tests on CFRP bonded steel plate joints was conducted. The joints were immersed in the temperature controlled sea-water with a preload. After immersions for one and six months, they were subjected to cyclic loading for a pre-set number of cycles, and then tensioned to failure. The effect of fatigue loading alone was studied by the authors in the past. In the present study, the results of the cyclic and static loading tests were compared. The comparisons between the current and previous results have provided data on the durability of CFRP/steel joints under this environmental condition.

The Effect of Elevated Temperature on the Bond Between High Modulus Carbon Fibre-Reinforced Polymer Sheet and Steel

The technique of strengthening steel structures with carbon fibre-reinforced polymer (CFRP) has attracted growing attention in research field and in practice, and thus, its environmental durability is of high importance. This paper describes an investigation on the bond characteristics between high modulus CFRP sheets and steel plates under elevated temperature exposures. Tensile tests were carried out on CFRP/steel plate double strap joints at different temperatures (20,40 and 50 °C) that represent the usually encountered conditions for civil infrastructure. High modulus (640 GPa) unidirectional carbon fibre sheets were applied by wet lay-up fabrication method. The fracture surfaces of the failed specimens were studied using a scanning electron microscope and the failure mechanisms were discussed. It was found that the ultimate load decreased significantly when the test temperature was above the glass transition temperature of the adhesive. Larger effective bond lengths were found for the joints tested at the glass transition temperature. It is obvious that the short-term thermal exposure has little effect on their failure patterns. All the specimens failed by fibre breakage at the joint and decohesion accompanied some joints with very short bond length.

TiB&lt;sub&gt;2&lt;/sub&gt;粒子複合高剛性鋼の切削加工に関する研究

High Young's modulus steel containing TiB2 particles is known as one of the difficult-to-cut materials. For this reason, a tool life becomes very short in machining of this material. The purpose of this study is to investigate extension of the tool life in the turning of high Young's modulus steel. The optimum cutting speed and cutting edge shape were examined from the viewpoint of tool life and surface roughness. The results indicated a dramatic decrease in the tool life of K10-C tool due to scratching of the flank wear region by hard TiB2 particles. On the other hand, the cutting edge of a binder less cBN tool with a negative land angle was protected by the built-up edge, leading to a decrease in the cutting force and an extension of the tool life. For this tool, it was clarified that from the viewpoint of wear resistance and the machined surface, the optimum conditions were a cutting speed of 1.0 m/s and a negative land angle of 15 degrees. It was shown that the presence of a secondary chip allows these conditions to be achieved, and that a built-up edge leads to stability.

B11 TiB_2粒子を含む高剛性鋼の切削特性に関する研究(OS-6 切削加工(2))

TiB_2-reinforced high modulus steel is expected to be weight saving of engine parts with important rigidity because this workpiece have high young's modulus and tensile strength. But existing coated carbide tool life has been shorted in machining of this workpiece because it was bad machinability. Then, the purpose of this paper is investigation which efficiency machining of TiB_2 reinforced high modulus steel using cBN tools (binder-less cBN, high content type cBN). As a result of tool wear test, it was found that the tool wear was much affected by cutting speed condition and cutting tool with and without negative land angle. Moreover, tool wear was inhibited by build up edge in tool wear test of low cutting speed. But high content type cBN toll life was shorted by delamination wear compared with binder-less cBN.

Mechanical behaviors of concrete combined with steel and synthetic macro-fibers

In this paper, hybrid fibers including high elastic modulus steel fiber and low elastic modulus synthetic macro-fiber (HPP) as two elements were used as reinforcement materials in concrete. The flexural toughness, flexural impact and fracture performance of the composites were investigated systematically. Flexural impact strength was analyzed with statistic analyses method; based on ASTM and JSCE method, an improved flexural toughness evaluating method suitable for concrete with synthetic macro-fiber was proposed herein. The experimental results showed that when the total fiber volume fractions (<TEX>$V_f^a$</TEX>) were kept as a constant (<TEX>$V_f^a=1.5%$</TEX>), compared with single type of steel or HPP fibers, hybrid fibers can significantly improve the toughness, flexural impact life and fracture properties of concrete. Relative residual strength RSI', impact ductile index <TEX>${\lambda}$</TEX> and fracture energy <TEX>$G_F$</TEX> of concrete combined with hybrid fibers were respectively 66-80%, 5-12 and 121-137 N/m, which indicated that the synergistic effects (or combined effects) between steel fiber and synthetic macro-fiber were good.

High modulus steel made by powder metallurgy : T.Saito. (Toyota Central R&D Laboratory, Aichi, Japan.) J. Jpn Soc. Powder Powder Metall., vol 45, no 5, 1998, 399–404. (In Japanese.)

High modulus steel made by powder metallurgy : T.Saito. (Toyota Central R&D Laboratory, Aichi, Japan.) J. Jpn Soc. Powder Powder Metall., vol 45, no 5, 1998, 399–404. (In Japanese.)

Phase equilibria in TiB2-reinforced high modulus steel

An application of thermodynamic calculations to the phase equilibria in TiB2-reinforced high modulus steel (HMS) is described. Titanium diboride (TiB2) has been verified as the best reinforcement for improving isotropic Young’s modulus of steels. The TiB2 particles can be synthesized in-situ in a ferrite matrix using a combination of ferrotitanium and ferroboron powders. The calculations reveal that impurities, such as oxygen, could promote the iron boride (Fe2B) formation in a Fe-TiB2 pseudobinary system, especially for the HMS processed through this powder metallurgical technique. Modification of the steel matrix of HMS by an addition of ferrite formers is encouraged based on the calculated (Fe-TiB2)-X diagrams that show no significant change in the stability of TiB2. In the development of HMS with an Fe-Cr matrix, the phase constitution was predicted successfully, and the highest Young’s modulus is reached with a proper control of titanium content.

TiB&lt;SUB&gt;2&lt;/SUB&gt;粒子強化型高剛性鋼の機械的性質と熱間加工性

TiB&lt;SUB&gt;2&lt;/SUB&gt;粒子強化型高剛性鋼の機械的性質と熱間加工性

TiB&lt;SUB&gt;2&lt;/SUB&gt;-フェライトの相平衡にもとづく高剛性鋼の開発

A new TiB2-reinforced steel with an enormously high Young's modulus has been developed for enabling a leaner design of automobile parts. This article describes the high modulus steel (HMS) with an emphasis on its microstructure and potential elastic properties based on the assessed phase equilibria in Fe-Cr-Ti-B system.The concept was to increase the isotropic Young's modulus by the optimum combination of reinforcing particles and steel matrices, and thermodynamic considerations strongly supported the most effective contribution of TiB2 to this purpose.Calculated phase diagrams located the narrow two-phase region of ferrite (α)+ TiB2 along the pseudo-binary system of (Fe-17Cr)-TiB2 in a wide temperature range. The proved phase stability and the small solubility of iron/chromium in TiB2 were considered most responsible for maintaining its own high modulus of 540 GPa in the steel matrix.In conventional powder metallurgy techniques, TiB2 particles were successfully dispersed in the matrix using commercial TiB2 powders, or synthesized through the in-situ reaction of ferro-titanium and ferro-boron powders.The measured Young's modulus of the HMS agreed well with the theoretically predicted value, and at 46 vol% TiB2, the specific modulus reached twice of those of conventional steels owing to its reduced density.