Increase In Vickers Hardness Research Articles

The influence of intermetallic ordering on wear and indentation properties of TiC-Ni3Al cermets

Cermets based on titanium carbide with a nickel aluminide binder (TiC-Ni3Al) offer potential as substitutes for tungsten carbide (WC) based hardmetals due to their high wear and corrosion resistance at ambient and elevated temperatures. In the current work, the effects of post-sinter heat treatments (between 600 and 1340 °C) on atomic ordering of the Ni3Al have been assessed through Vickers indentation, scratch testing and computational modelling. Changes in the atomic structure are evidenced from X-ray diffraction by abrupt increases in the (111) and (200) peak intensities. An increase in Vickers hardness, from 1400 to 1530 HV, is observed as a result of heat treatment at 1200 °C. Furthermore, the scratch hardness value was improved from 11.89 to 18.12 GPa, with the main wear mechanisms being identified as TiC grain pull out and brittle fracture. Ordering transitions were subsequently related to the structural changes predicted through ab-initio modelling approaches.

Grinding mechanism and mechanical properties of the in-situ synthesized Al2O3/TiAl composites

Abstract In-situ synthesis of Al2O3/TiAl composite was carried out by mechanical milling of the pre-alloy Ti-45Al-7Nb-0.3W and TiO2 powder mixture and subsequent sintering by spark plasma sintering (SPS) technique. The mixed powders experienced the initial destructive breakage stage, cold welding package stage and breaking up of boulders stage during mechanical milling. The particle size obviously declined with the mechanical milling time increasing. The number-average diameter (D(1,0)) of as-milled powders rapidly reduced from 75.0 μm to about 15.5 μm, and its distribution uniformity (U) decreased to 0.55 when milling time increased to 20 h. Nano Al2O3 particles had been formed during milling. The as-SPSed compacts were mainly composed of γ-TiAl phases, α2-Ti3Al phases and nano-Al2O3 particles that tended to disperse both on the grain boundaries and inside the lamellar microstructure of the matrix. The contents of A12O3 increased from 4.3% to 8.9 vol% as the milling time increased from 10 to 20 h. The increasing concentration led to the increase in Vickers hardness of Al2O3/TiAl composites, and a maximum value of 6.2 GPa was achieved. A corrected mixture rule was constructed which can predict the hardness of the composites accurately. The ultimate compression strength (UCS) increased firstly and then decreased with prolonging milling time. The highest value of 1848 MPa was obtained when the mixed powders milled for 15 h, i.e., the fraction of Al2O3 in the TiAl matrix was 7.6 vol%.

Raman spectroscopic studies of stress-induced structure alteration in diamond-like carbon films

In this paper, Raman spectral mappings were carried out on Vickers indentation prints introduced on DLC films prepared with different substrate bias voltages (SBV). The mapping results showed clear differences in the intensity ratio, ID/IG, and band shifts for D and G peaks in samples fabricated with and without applying SBV. These spectral characteristics arose from the cumulative effect of a compressive (residual) stress field and structural alterations including sp2 and sp3 carbon disorder upon generation of the indentation print. Additional quantitative stress analyses, which employed spectral line scans on the film cross sections, revealed clear differences in magnitude for the compressive stresses stored in the films, as well as in-depth structural variations resulting from different SBV being applied during fabrication. An increasing level of residual compressive stress in the DLC films with increasing SBV may directly contribute to the observed decreased adhesion to the substrates and to the increased Vickers hardness.

Microstructural evolution, mechanical and thermal properties of TiC-ZrC-Cr3C2 composites

Dense TiC-ZrC-Cr3C2 composites with various TiC content from 19.6 mol% to 78.4 mol% have been fabricated by hot-pressing sintering at 1950 °C using 2.0 mol% Cr3C2 as sintering aid. The effect of TiC content on the microstructure, mechanical and thermal properties of TiC-ZrC-Cr3C2 composites are investigated systematically. The single (Zr, Ti, Cr)C solid solution is obtained when TiC content is 19.6 mol%, while with increasing TiC content, the composites begin to consist of Zr-rich (Zr, Ti)C solid solution and Ti-rich (Ti, Zr, Cr)C solid solution phase. SEM and EDS analysis confirm that Cr element is not favorable to diffuse into ZrC lattice to form (Zr, Cr)C solid solution. Flexural strength and Vickers hardness increase gradually with increasing TiC content, but fracture toughness does not improve significantly. Fracture toughness are in the range of 3.34–4.01 MPa∙m1/2 for all composites, and the optimum value reaches 4.01 MPa·m1/2 with 49.0 mol% TiC. Experimental results of the thermal expansion coefficient reveal that the addition of TiC raises the thermal expansivity of TiC-ZrC-Cr3C2 composites. Noticeably, the thermal conductivities of TiC-ZrC-Cr3C2 composites show a decrement trend with increasing TiC content, not as theoretical predicting by the rule of mixtures. For instance, the thermal conductivity at 25 °C ranges from 18.0 W/m∙K for 8Z2T2C composite down to 10.6 W/m∙K for 2Z8T2C composite.

Mechanical Properties and Very High Cycle Fatigue Behavior of Peak-Aged AA7021 Alloy

The effect of heat treatment condition on non-Cu AA7021 alloy was investigated with respect to mechanical properties and very high cycle fatigue behavior. With a focus on the influence of heat treatment, AA7021 alloy was solution heat-treated at 470 °C for 4 h and aged at 124 °C. Comparing the results of solution-treated and peak-aged AA7021 alloy shows a significant increase in Vickers hardness and tensile strength. The hardness of AA7021 alloy was increased by 65% after aging treatment, and both tensile strength and yield strength were increased by 50~80 MPa in each case. In particular, this paper investigated the very high cycle fatigue behavior of AA7021 alloy with the ultrasonic fatigue testing method using a resonance frequency of 20 kHz. The fatigue results showed that the stress amplitude of peak-aged AA7021 alloy was about 50 MPa higher than the solution-treated alloy at the same fatigue cycles. Furthermore, it was confirmed that the size of the crack initiation site was larger after peak aging than after solution treatment.

Processing of AISI H11 Tool Steel Powder Modified with Carbon Black Nanoparticles for the Additive Manufacturing of Forging Tools with Tailored Mechanical Properties by Means of Laser Metal Deposition (LMD)

Within the scope of the presented work the processing of AISI H11 (1.2343 or X37CrMoV5-1) tool steel powder modified by adding carbon black nanoparticles in varying concentrations by means of Laser Metal Deposition (LMD) is extensively investigated. On the basis of single weld track experiments, multi-layered cuboid-shaped samples made out of pure AISI H11 tool steel powder as well as modified tool steel powder mixtures were manufactured by applying various process parameters. The main scientific aim of the investigations was to achieve a basic understanding of the influence of the added carbon black nanoparticles on the resulting sample properties. For that purpose, the generated specimens were first analyzed with respect to relative density, inner defects, microstructure, Vickers hardness and chemical composition. Subsequently, the mechanical properties of post-heat-treated specimens were investigated, with the focus on the yield strength (Y0.2%), by means of compression tests. We prove that by adding carbon black nanoparticles to the initial AISI H11 powder, the formation of martensitic and bainitic phases, as well as the precipitation of carbides at the grain boundaries, are enhanced. As a result, a significant increase of Vickers hardness and of the compression yield strength by up to 11% can be achieved in comparison to samples made out of the unmodified AISI H11 powder. Furthermore, it can be fundamentally demonstrated that the fabrication of parts with layer-specific variable hardness can be realized by the controlled changing of the powder mixtures used during the layer-by-layer manufacturing approach.

Influence of phase composition on thermal aging behavior of plasma sprayed ytterbium silicate coatings

In this study, ytterbium silicate coatings with different phase compositions were designed by controlling Yb2O3/SiO2 ratio and fabricated by atmospheric plasma spray (APS) technique. Thermal aging behaviors such as microstructure evolution and thermomechanical properties were focused, and the influence of phase composition was analyzed. Results showed that obvious grain growth and defect reduction occurred, and the thermomechanical properties were significantly modified after thermal aging. The larger reduction in defects and greater increase in elastic modulus, Vickers hardness and coefficient of thermal expansion took place in the Yb2O3-rich coatings containing Yb2O3 and Yb2SiO5 phases. The bigger grains and transgranular cracks were formed and the greater increase in thermal conductivity took place in the SiO2-rich coatings containing Yb2SiO5 and Yb2Si2O7 phases. The relationship among microstructure evolution and variation of thermomechanical properties was analyzed. The results of this study may provide a reference for design and application of rare-earth silicates as environmental barrier coatings (EBCs).

In-situ TiC-Graphite-Ni hybrid composites innovatively fabricated by pressureless reactive infiltration method

TiC-Graphite-Ni hybrid composites integrating high hardness of TiC, lubrication of graphite and good fracture toughness of Ni, present excellent tribological properties. This paper innovatively fabricates in-situ TiC-Graphite-Ni composites by pressureless reactive infiltration method, which is simple, low cost and applicable for composites with large and complex shape. The composition of composites is altered by designing C/Ti molar ratio in preforms. In-situ TiC and graphite homogeneously distribute in metal matrix with clean interface. Results show that the graphite content also affects the formation process of in-situ TiC. As C/Ti molar ratio increases from 1 to 1.5, graphite content in composites increases from 0 to 2.7 wt%, and TiC particle size reduces from 3.03 μm to 2.58 μm, resulting in the increase of Vickers hardness of composites from 527 to 664 HV2. With addition of TiC and graphite, tribological properties of Ni-based alloy are improved, which becomes more obvious as graphite content increases. The friction coefficient of composite with 2.7 wt% graphite is 19% lower than that of Ni-based alloy. The main wear mechanism of composites is abrasive wear.

Fabrication and characterization of WC-AlCoCrCuFeNi high-entropy alloy composites by spark plasma sintering

Mechanically alloyed AlCoCrCuFeNi high-entropy alloy (HEA) powders were used as binder to fabricate WC/HEA composites by spark plasma sintering. The effects of sintering temperature, duration time and binder content on microstructures and mechanical properties were studied. Compared with cobalt binder, the HEA binder has an advantage on the inhibition of WC grain growth due to the sluggish diffusion effect, and the average WC grain size decreases with increasing HEA binder content. Furthermore, the fracture toughness of WC/HEA composites firstly increases with increasing Vickers hardness and then decreases. A good comprehensive mechanical property was obtained after sintering at 1250 °C for 5 min with 10 wt.% HEA binder under a sintering pressure of 30 MPa. The Vickers hardness is 1922 HV30 and the fracture toughness is 10.41 MPa m1/2, which are higher than those of commercial WC/Co composites. Therefore, the AlCoCrCuFeNi high-entropy alloy has a potential to be a binder for WC.

Comparative investigation on microstructures and mechanical properties of (TiB + TiC)/Ti-6Al-4V composites from Ti-B4C-C and Ti-TiB2-TiC systems

Two percentages of TiB + TiC reinforced Ti-6Al-4V composites from Ti-B4C-C and Ti-TiB2-TiC systems were fabricated by reactive hot-pressed sintering. Their microstructures and mechanical properties involving elastic modulus, Vickers hardness, bending strength and wear property were investigated comparatively. The experimental results show that needle-like TiB whiskers and near-equiaxed TiC particles are evenly distributed in the Ti-6Al-4V matrix. The mechanical properties of the (TiB + TiC)/Ti-6Al-4V composites are closely related with the nominal composition and synthesis system of TiB + TiC reinforcement and the microstructures of composites. With increasing the nominal volume fraction of reinforcement, both elastic modulus and Vickers hardness increase more or less and the bending strength decreases in varying degrees. A certain increase of pores in the composites with the sintering temperature increasing to 1300 °C can markedly affect the bending strength. Moreover, no matter what the sintering temperature and nominal volume fraction of reinforcement, the elastic modulus and Vickers hardness of composites from the Ti-TiB2-TiC system are higher than those from the Ti-B4C-C system. Similarly, the composites from the Ti-B4C-C system present better abrasion resistance than those from the Ti-TiB2-TiC system due to the difference of interfacial bonding between the TiC particles and Ti-6Al-4V matrix in the two kinds of composites.

Changes induced in structure and optical properties of PM-355 nuclear track detector due to laser irradiation

ABSTRACTPM-355 is a class of polymeric solid-state nuclear track detectors which has a lot of applications in several radiation detection fields. Samples from sheets of PM-355 have been exposed to infrared (IR) laser fluences ranging from 1 to 12.8 J/cm2. The effect of IR laser radiation on the structural properties of PM-355 has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the samples exhibit chain scission under the effect of laser irradiation up to 4.2 J/cm2, thus producing free radicals that led to the formation of new bonds started and continued until 12.8 J/cm2. This reduces the ordering structure, giving the PM-355 polymer more resilience. In addition, the laser irradiation at the fluence range 4.2–12.8 J/cm2 led to a more compact structure of PM-355, which resulted in an improvement in its isotropic nature with an increase in Vickers hardness and refractive index. Further, the color changes due to laser irradiation were computed using the transmission data in the wavelength range of 370–780 nm. It is found that the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the laser fluence, largely depending on the proportions of the blue color component.

Surface Characterization and Cell Adhesion of Different Zirconia Treatments: An in vitro Study.

The aim of this study was to characterize the surface of zirconia subjected to different treatments and evaluate its effect on cell adhesion and proliferation. A total of 80 zirconia disks were divided into four groups (n = 20) according to the surface treatments used: group I: as-sintered (AS), no surface treatment applied; group II: abrasion treatment applied using Rocatec (ROC; 3M ESPE) system with silica-coated alumina powder of grit size 110 μm; group III: erbium, chromium:yttrium, scandium, gallium, garnet (Er, Cr:YSGG) laser (LAS; BIOLASE) was used at a frequency of 20 Hz and output power of 3 W; and group IV: specimens were subjected to the selective infiltration etching (SIE) technique. Surface characterization was evaluated for the different groups (roughness, hardness, and morphology), and cell behavior (adhesion and proliferation) was tested (a = 0.05). The ROC group reported a significant increase in surface roughness (2.201 ± 0.352) and Vickers hardness (1758 ± 16.6) compared with the other surface treatments. The SIE surface-treated group reported a significantly higher number of cells (64.5 ± 2.6 and 53.5 ± 2.2 respectively) compared with the other surface-treated groups. The SIE is a promising surface treatment for zirconia that significantly enhances cell adhesion and osseointegration. The SIE treatment of zirconia implants may help in a faster and better osseointegration.

Achieving high thermal and mechanical properties of epoxy nanocomposites via incorporation of dopamine interfaced clay

The uniform dispersion of clay in epoxy matrix and strong interfacial bonding between clay platelet and epoxy chains are crucial for achieving epoxy/clay with enhanced thermal and mechanical properties. In this study, dopamine hydrochloride was intercalated into the galleries of clay via ion‐exchange reaction with an aim to improve the dispersion and interfacial bonding with the epoxy matrix. Dopamine intercalated clay (D‐clay) was characterized by X‐ray photoelectron spectrum, Fourier Transform Infrared Spectroscopy, and X‐ray diffraction (XRD), respectively. Epoxy/D‐clay nanocomposites had been prepared by curing process of epoxy E51, Jeffamine D230, and D‐clay with 1, 2, 3, and 4 wt%, respectively. The structure of epoxy/D‐clay nanocomposites was characterized by XRD, scanning electron microscopy, and Transmission electron microscopy, respectively. The enhanced thermal properties and mechanical properties such as tensile strength, tensile modulus, and hardness were enhanced considerably compared with neat epoxy resin. The results found that the inclusion of 3 wt% D‐clay in the epoxy resin showed increase in Tg of 10.09°C, 29.34% increase in tensile strength, 23.19% increase in tensile modulus, and 53.87% increase in vickers hardness compared with neat epoxy resin. The uniform dispersion of clay platelets and strong interfacial hydrogen bonding between D‐clay and epoxy matrix afforded efficient load transfer across the epoxy‐clay interface, leading to significantly improved thermal and mechanical properties. POLYM. COMPOS., 39:E2407–E2414, 2018. © 2017 Society of Plastics Engineers

Preparation of Mullite–TiC–TiN Materials by a Plasma Spark Method and Their Properties

The phase composition of synthesized TiC and TiN, microstructure, relative density, open porosity, linear shrinkage, elasticity modulus, Vickers hardness, ultimate strength in compression, and linear dependence of elasticity modulus and ultimate strength in compression of mullite–TiC–TiN-specimens with a different ratio of TiC and TiN sintered by a plasma-arc method in the range 1200 – 1600°C with a compaction load of 30 MPa, are studied. Synthesized powders have intense crystallization of TiC and TiN. Sintered specimens with a different ratio of TiC and TiN demonstrate intense mullitization in the range 1200 – 1600°C. Specimens with a TiC/TiN ratio of 50/50, 70/30, and 90/10 mol.% demonstrate a gradual increase in TiC from 1200 – 1400°C compared with a more intense increase in TiC from 1400 to 1600°C. An increase in TiC concentration and a reduction in TiN content in powder mixtures sintered at 1500°C facilitates formation of a uniform density sintered microstructure with presence of small pores. Specimens in the ratios TiC/TiN of 50/50 and 70/30 mol.% point to a more intense increase in relative density and linear shrinkage; a reduction in open porosity and an increase in elasticity modulus, Vickers hardness, and ultimate strength in compression. This leads to an increase in specimen crack formation resistance in the presence of microcracks with a relatively rectilinear propagation trajectory (composition M50TiC50TiN), and absence of microcracks (composition M70TiC30TiN) around an indenter impression, with the greatest linear dependence of elasticity modulus and ultimate strength in compression in the range 1200 – 1600°C.

Fabrication of infrared-transparent 3Y-TZP ceramics with small grain size by pre-sintering in an oxygen atmosphere and hot isostatic pressing

Infrared-transparent 3mol% tetragonal zirconia polycrystalline (3Y-TZP) ceramics with small grain size were fabricated by pre-sintering in an oxygen atmosphere and hot isostatic pressing (HIP). The microstructure, mechanical, optical, and elevated-temperature properties of the ceramics were investigated. Pre-sintering in an oxygen atmosphere suppressed the grain growth effectively, and the grain size reached approximately 138nm. The small grain size led to an increased Vickers hardness of 13,790MPa. The ceramics also exhibited a high transmittance of 76–78% in the range of 3–5µm. The in-line transmittance remained stable with the temperature elevated to 400°C. Overall, the results indicated that pre-sintering in an oxygen atmosphere and HIP was an effective method to prepare infrared-transparent 3Y-TZP ceramics with small grain size.

Fabrication and mechanical properties of WC-Al2O3 cemented carbide reinforced by CNTs

Carbon nanotubes (CNTs) reinforced WC-Al2O3 cemented carbides were prepared by hot pressing technique. The microstructure and components of composites were studied by Scanning Electron Microscope (SEM), Laser Raman spectroscopy and X-ray diffraction (XRD). The hardness and fracture toughness were analyzed by Vickers hardness tester. The experimental results showed that the WC-Al2O3-CNTs composite exhibited a significant increase in fracture toughness and Vickers hardness compared with WC-Al2O3 composite, which could be ascribed to evolution of microstructure resulted from the incorporation of CNTs. The minimum value of grain size was obtained in the WC-Al2O3-CNTs-0.5 cemented carbide and that sample possessed a better mechanical property compared with other WC-Al2O3 cemented carbides. The properties of the composite decreased sharply when the content of CNTs in WC-Al2O3 cemented carbide surpassed 1 wt %. The toughening and strengthening mechanisms of WC-Al2O3-CNTs cemented carbide including crack bridging, CNTs debonding, crack deflection and pull-out were studied respectively.

Precipitation of Nano-Sized Carbides in a Ti-Mo Bearing Steel at a Low Transformation Temperature

While the role of Ti and Mo elements on precipitation strengthening in ferrite grains formed during austenite/ferrite transformation is very clear, some uncertainty still presents concerning influence of microalloying elements on bainite transformation. Therefore, the present study focuses on the precipitation behavior occurred in a Ti-Mo bearing steel during bainitic phase transformation under different heat treatment conditions, and the correlation of the precipitation behavior with hardness distribution. Through the present work, it is expected to achieve a better understanding of low-temperature precipitation behavior to assist metallurgists to find out the reason for maintaining a high hardness by longtime isothermal holding, which can provide insight to design a better quality steel product. Vickers hardness was measured from the 1C-2Ti-2Mo, 1C-2Ti-2Mo and 0.5C-1Ti-2Mo steels treated by isothermal holding at 550 oC for 5 to 60 min. The average Vickers hardness was in the range of 245 - 276, 290 - 335 and 220 - 245, respectively. Therefore, higher hardness can be obtained if the steel containing higher carbon and microalloying elements can form precipitations in the ferrite matrix. On the other hand, increasing Vickers hardness with isothermal holding times indicates a good thermal stability character of complex carbides. The excellent thermal stability can be attributed to the addition of Mo element, which can inhibit the growth of carbides during longtime isothermal holding. Furthermore, the addition of Mo in the steel can avoid annihilation of dislocations during longtime aging. By taking advantages of these two effects, high strength can be achieved for high-strength low-alloy steels containing Mo element. Transmission electron microscopy image showed nano-sized carbides nucleated at dislocations, instead of interfacial precipitations within ferrite grain matrix, because the interface precipitation morphology only occurred accompanying the austenite decomposition reaction. However, the bainitic phase transformation was of a displacive transformation character, thus the complex carbides could not form during the bainitic phase transformation due to a very fast transformation velocity.

Strengthening and toughening of TiN-based and TiB2-based ceramic tool materials with HfC additive

Effects of HfC addition on the microstructures and mechanical properties of TiN-based and TiB2-based ceramic tool materials have been investigated. Their pore number decreased gradually and relative densities increased progressively when the HfC content increased from 15wt% to 25wt%. The achieved high relative densities to some extent derived from the high sintering pressure and the metal phases. HfC grains of about 1µm evenly dispersed in these materials. Both TiN and TiB2 grains become smaller with increasing HfC content from 15wt% to 25wt%, which indicated that HfC additive can inhibit TiN grain and TiB2 grain growth, leading to the formation of a fine microstructure advantageous to improve flexural strength. Especially, TiB2-HfC ceramics exhibited the typical core-rim structure that can enhance flexural strength and fracture toughness. The toughening mechanisms of TiB2-HfC ceramics mainly included the pullout of HfC grain, crack deflection, crack bridging, transgranular fracture and the core-rim structure, while the toughening mechanisms of TiN-HfC ceramics mainly included pullout of HfC grain, fine grain, crack deflection and crack bridging. Besides, HfC hardness had an important influence on the hardness of these materials. Higher HfC content increased Vickers hardness of TiN-HfC composite, but lowered Vickers hardness of TiB2-HfC composite, being HfC hardness higher than for TiN while HfC hardness is lower than for TiB2. The decrease of fracture toughness of TiN-HfC ceramic tool materials with the increase of HfC content was attributed to the formation of a weaker interface strength.

Effects of pressure on densification behaviour, microstructures and mechanical properties of boron carbide ceramics fabricated by hot pressing

Effects of pressure, from ordinary (30MPa) to high pressure (110MPa), on densification behaviour, microstructures and mechanical properties of boron carbide ceramics sintered by hot pressing are investigated. With increasing pressure, the relative density sharply increases within 30–75MPa, slowly increases within 75–100MPa and finally stagnates. For samples within 75–100MPa, densification begins at approximately 1000°C, and the dominant densification process ends before the soaking stage. High relative densities of 98.49% and 99.76% are achieved. For samples within 30–50MPa, densification begins at approximately 1500°C, and the soaking stage (initial 20min) is still important for the dominant densification process. The final relative densities are only 87.90% and 92.32%. The above-mentioned differences are derived from contributions of pressure, and the dominant densification mechanism under high pressure is plastic deformation. The average grain size of the samples slightly increases with increasing soaking time. The grain size under higher pressure is larger than that under lower pressure at corresponding periods because grains grow easily with reduced pores. Vickers hardness and fracture toughness increase as grain size decreases in fully dense samples. However, when the samples do not achieve full density, relative density becomes more influential than grain size in hardness and toughness. A soaking time of 30min is enough for samples under 100MPa. Prolonging the soaking time has deleterious effects on mechanical properties. The relative density, grain size, hardness and fracture toughness of the samples under 100MPa for 30min are 99.73%, 1.96µm, 37.85GPa and 3.94MPam1/2, respectively.

High entropy effect on structure and properties of (Fe,Co,Ni,Cr)-B amorphous alloys

We examined high entropy (HE) effect on the formation, structure, thermal stability, mechanical properties and corrosion behavior for (Fe,Co,Ni,Cr)100-xBx (x = 18–26) amorphous alloys in comparison with Fe100-xBx amorphous alloys. The as-quenched structure consists of an amorphous single phase for the 18–24%B alloys, and amorphous + tetragonal Cr5B3 phases for the 26%B alloy. The broad diffraction peak position due to amorphous phase shifts to a higher wave vector side with increasing B content for the HE alloys, while that of the Fe-B alloys changes to the lower wave vector side, indicating the distinct difference in disordered atomic structure between the HE alloys and the binary alloys. All the as-spun HEA ribbons exhibit good bending ductility in spite of the coexistence with their crystalline phases, being different from the brittle nature for the 26%B binary alloy. The crystallization temperature (Tx) and Vickers hardness (Hv) increase with increasing B content, show maximum values of 803 K and 1130, respectively, at 22%B and then decrease to 793 K and 1070, respectively at 26%B, being different from the nearly constant Tx and almost linear increase in Hv with increasing B content for the Fe100-xBx alloys. The corrosion resistance in NaCl, H2SO4 and HCl solutions evaluated by potential and anode current density is much better for the HE alloys as compared with the Fe-B alloys. Thus, the Tx, Hv, bending ductility and corrosion resistance for the HE amorphous alloys containing more than 20 at%B are much superior to those for the Fe-B amorphous alloys. The fully crystallized structure consists of fcc + FeB + Fe2B + Cr5B3 phase for the HE 22–26 at%B alloys and bcc-Fe + Fe2B for the Fe-B alloys. The significant improvement of the fundamental properties caused by the HE component modification is presumably due to the formation of Cr-B pair with higher B-rich components. The improved properties in conjunction with the change in the disordered structure for the HE amorphous alloys provide an opportunity of developing a new functional material by alloy design to HE type compositions.