Good Bending Ductility Research Articles

Effect of microalloying on crystallization behavior, magnetic properties and bending ductility of high Fe content FeSiBCuPC alloys

Effect of microalloying on microstructure, magnetic properties and bending ductility of the Fe85.7-85.8Si0.5B9-9.3P3.5-4Cu0.5-0.8C0.2-0.3 alloy ribbons with high Fe content was systematically investigated. It is found that the substitution of 0.1 at. % Cu or 0.2 at. % Cu for (B+P) content inhibits the crystallization and improves the amorphous forming ability of melt-spun Fe85.7-85.8Si0.5B9-9.3P3.5-3.9Cu0.6-0.7C0.2-0.3 alloys. The first crystallization temperature (Tx1) increases slightly with the addition of C or P content, while the second crystallization temperature (Tx2) exhibits a slightly decrease. All amorphous alloys exhibit a large temperature interval between Tx1 and Tx2, which contributes to the thermal stability and leads to the formation of a single α-Fe phase. In the as-spun state, the amorphous alloys have good bending ductility even at high Fe content. After the optimum heat treatments, the Fe85.7-85.8Si0.5B9-9.3P3.5-3.9Cu0.6-0.7C0.2-0.3 nanocrystalline alloys exhibits the excellent soft magnetic properties, such as the highest Ms of 206.4–210.2 emu/g (Bs ≈ 1.95–1.98 T) and the lowest Hc of 6.5–8.4 A/m.

Soft magnetic properties of Fe82-83B14-15Si2C0.5-1 amorphous alloys with high saturation magnetization above 1.7 T

With the aim of developing a new inexpensive soft magnetic amorphous alloy exhibiting high saturation magnetic flux density (Bs) above 1.7 T, we examined the formation, thermal stability and magnetic properties for melt-spun Fe-B-Si-C amorphous alloys with high (B + C)/Si content ratios. The high Bs of 1.71–1.73 T exceeding the previously reported Bs was obtained for annealed Fe82-82.5B15Si2C0.5-1 alloys. These high Bs alloys exhibit low coercivity below 8 A/m and good bending ductility. The 82.5Fe alloy with the highest Bs of 1.73 T also has the highest hardness. Besides, the 82.5Fe alloy has the largest nearest neighbor atomic distance among the present alloys. The correlation between the highest Bs and the largest atomic distance is similar for (Fe,Co)83-86B15-16Si1 amorphous alloys. The 82.5Fe and 82Fe alloys are located near the critical composition where the crystallization changes from two stages of α-Fe(Si) + amorphous ⇢ α-Fe(Si) + Fe3(B,C) to a single stage of α-Fe(Si) + Fe3(B,C). These results indicate the importance of the special alloy composition with the largest atomic distance and high stability to primary α-Fe precipitation, in addition to high (B + C)/Si content ratios, for the synthesis of a new ductile amorphous alloy with high Bs and good magnetic softness.

Plastic deformation behavior of a novel Fe-based metallic glass under different mechanical testing techniques

A novel Fe-based metallic glass (Fe0.52Co0.30Ni0.18)73Cr17Zr10 without metalloids has been prepared. Its mechanical properties and plastic deformation behavior have been investigated systematically by bending test, tensile test and Vickers indentation test. This metallic glass ribbon exhibits good bending ductility, but it shows catastrophic brittle fracture in tensile tests. The Vickers hardness is 904.4 HV, which is higher than most of used quenched steel, manifesting the possibility of good wearability. Under different indentation forces, the plastic deformation of indentation is adjusted through radial and semi-circular shear bands. The average indentation size(D) and the radius of plastic deformation zone(R) increases with increasing indentation forces(P). The normalized shear deformation zone(R/D) is unrelated with indentation forces.

Effect of V addition on the performance of Fe73.5Cu1B13Si9.5Nb3-xVx soft magnetic alloys

The soft magnetic alloys Fe73.5Cu1B13Si9.5Nb3-xVx (x = 0, 0.5, 1.0, 1.5) were prepared by melt-spinning. The effects of doping V and annealing process on the microstructure, magnetic properties and bending ductility of the alloys were investigated. Results show that doping V can improve the glass formation ability for the alloys. It is found that the large thermal stability value (ΔT), which is beneficial to enhance the soft magnetic properties, can be obtained by tuning the first crystallization temperature and the second crystallization temperature with doping V. The alloys exhibit high saturation magnetization of about 155.9 emu/g. Furthermore, the coercivity (Hc) of 1.9 A/m and permeability of 152500 measured at 10-170 KHz near room temperature are obtained. Moreover, the good bending ductility makes Fe73.5Cu1B13Si9.5Nb2V1 alloy as a candidate for widely used in the fields of mechanical, chemistry and medicine.

Novel deformation-induced polymorphic crystallization and softening of Al-based amorphous alloys

Melt-spun amorphous ribbons of Al90Y10 (at.%) (90Al) and Al84Y8.5Ni4Co2Pd1Fe0.5 (84Al) are cold-rolled at near to liquid-nitrogen temperature or at room temperature, inducing partial crystallization to nanoscale fcc-Al (α-Al). The crystallization is characterized and contrasted with the distinct sequences of reactions on annealing 90Al and 84Al amorphous alloys. Rolling-induced crystallization leads to softening, opposite to the effect of nanocrystallization induced by annealing. The origins of the hardness changes are analyzed. The rolling induces novel polymorphic crystallization to α-Al with extended solid solubility. This transformation, which occurs equally in 84Al and 90Al, despite the much greater thermal stability of the former, allows the ribbons to retain good bending ductility, and delays the onset of embrittlement on subsequent annealing. Partial crystallization induced by cold-rolling is useful in avoiding the formation of compound phases associated with brittleness, and is a promising process for high-solute Al-based amorphous alloys to be further developed as structural materials.

Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ∼35 μm possesses a high saturation magnetization (Bs) of ∼1.78 T, low coercivity of ∼14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513–553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

Liquid ejection temperature dependence of structure and glass transition behavior for rapidly solidified Zr-Al-M (M=Ni, Cu or Co) ternary glassy alloys

The appearance/disappearance of glass transition (GT) and supercooled liquid (SL) region was found to be affected for Zr-Al-(Ni, Cu, Co) glassy ribbons by changing the ejection temperature (Te) in the range from liquid temperature (Tl)+200 K (LT) to Tl+700 K (HT). The Te at which the disappearance occurs lies around 600–700 K above Tl. The oxygen contents increase from 240 to 550 ppm for LT samples to 990–4440 ppm for HT samples, but their contents are lower than those (4000–5000 ppm) for the samples with GT and SL region. The AES analyses show that the oxygen was segregated to the thin surface region. As compared with LT samples, HT samples exhibit higher hardness and glass transition temperature (Tg), while keep good bending ductility. Structure analyses using high energy X-ray diffraction and MD simulations show the change to looser atomic configurations for HT sample. The disappearance of GT for HT samples reflects the change of liquid structure from icosahedral-like medium-range ordered structure to a less-coordinated atomic structure. The GT appears again by ejection after the lowering of Te from Tl+700 K to Tl+300 K. The Te dependence of GT together with the changes in Tg and hardness is encouraging for novel material science/engineering field through the control of liquid structures.

Formation, thermal stability and mechanical properties of high entropy (Fe,Co,Ni,Cr,Mo)-B amorphous alloys

The formation, thermal stability and mechanical properties of high entropy (HE) (Fe0.25Co0.25Ni0.25Cr0.125Mo0.125)100-xBx (x = 11–31 at%) amorphous alloys were examined with the aim of clarifying the partial replacement effect of Cr by Mo in comparison with previously reported HE (Fe0.25Co0.25Ni0.25Cr0.25)100-xBx amorphous alloys. The amorphous phase was formed in a very wide B range of 11–31 at%, and crystallization temperature (Tx) and Vickers hardness (Hv) increased with increasing B content. The peak position of the X-ray diffraction patterns shifts to the higher diffraction angle side with increasing B content, implying the development of denser coordinated atomic configuration. There is a good linear relation between Hv and the angle shift of the peak position in the broad diffraction pattern. The crystallization mode changes from Am → fcc + Am for the 15–20 at% B alloys to Am → glass transition (GT) →M23B6 for the 25 and 27 at% B alloys. It is noticed that the GT is observed for the alloys with 22–31 at% B. The good bending ductility is obtained for the alloys up to 25 at% B and the ductile 25 at% B alloy exhibits high Tx and high Hv. Considering the previous data that the Mo-free amorphous alloys are formed in the limited B range of 18–22 at% B and do not show the GT, the partial replacement of Cr by Mo is effective for the increase in glass-forming ability and Hv through the development of more coordinated atomic configuration resulting from the increase in the level of satisfaction of the three component rules for stabilization of supercooled liquid. The interpretation is also supported from the differences in the calculated entropy parameters between the HE amorphous alloys and HE crystalline solid solution alloys. The first formation of an amorphous phase for the lower and higher B content alloys of 11–14 and 26–31 at% is also promising for future application to structural materials.

Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

Effect of the substitution of C for Si on microstructure, magnetic properties and bending ductility in high Fe content FeSiBCuPC alloy ribbons

The microstructure, magnetic properties and bending ductility of the Fe85Si1.5-xB9Cu0.5P4Cx (x = 0, 0.1 0.2, 0.3, 0.4, 0.5) alloy ribbons with high Fe content were investigated. The partial substitution of C for Si increases the amorphous forming ability and enlarges the maximum thickness of glassy from 19 μm to 25 μm of the alloys. It is clearly seen that the addition of C increases the first crystallization temperature (Tx1), while the reduction of Si slightly decreases the second crystallization temperature (Tx2). The amorphous alloys exhibit the low Curie temperature (Tc), and large Tx1 - Tc allows the alloys to obtain better soft magnetic properties. In amorphous state, with the increase of C, the saturation magnetization (Ms) and the coercivity (Hc) of the amorphous alloys descend slightly, which decrease from 168.0 emu/g to 166.8 emu/g and 10.0 A/m to 9.3 A/m, respectively. Through the optimum annealing treatments, the Fe85Si1.4B9Cu0.5P4C0.1 nanocrystalline alloy exhibits highest Ms of 205 emu/g (Bs ≈ 1.93 T) and lowest Hc of 5.8 A/m. Both of the amorphous alloys exhibit good bending ductility before and after annealing.

Development of soft magnetic amorphous alloys with distinctly high Fe content

This paper reports on the preparation of Fe82.7-85.7Si2-4.9B9.2-11.2P1.5-2.7C0.8 soft magnetic amorphous alloys with a distinctly high Fe content of 93.5-95.5 wt.% by component design and composition adjustment. All alloys can be readily fabricated into completely amorphous ribbon samples with good surface quality by the single copper roller melt-spinning method. These alloys show good bending ductility and excellent magnetic properties after annealing, i.e., low coercivity ( H c) of 3.3-5.9 A/m, high permeability ( μ e) of 5000-10000 and high flux saturation density ( B s) of 1.63-1.66 T. The mechanism of the good glass forming ability (GFA) and soft-magnetic properties are explored. The amorphous alloys with the high Fe content comparable to that of the desired high Si alloy can be promising candidates for the potential application in electric devices.

Soft magnetic Fe-Co-based amorphous alloys with extremely high saturation magnetization exceeding 1.9 T and low coercivity of 2 A/m

Extremely high saturated magnetization (Bs) of 1.92 T in conjunction with low coercivity (Hc) of 2 A/m was found to be achieved for (Fe0.8Co0.2)85B14Si1 amorphous alloy. The high Bs above 1.9 T was the first evidence for amorphous alloys. The slight increase of B to 15%B reduces Bs to 1.88 T. The high Bs of 1.92 T is much higher than that (1.63 T) for the new commercial Fe-B-Si-C amorphous alloy and comparable to commercial Fe-Si steels. The excellent soft magnetic properties, which cannot be obtained for all soft magnetic alloys including amorphous, nanocrystalline and crystalline alloys reported to date, were obtained by annealing the as-spun amorphous alloy ribbon for 600 s at 593 K in a magnetic field of 15.9 kA/m. The high Bs above 1.9 T was obtained in a rather wide annealing conditions of 543–603 K and 300–1200 s, indicating the ease of achieving the excellent soft magnetic properties. No appreciable crystalline phase is recognized in the annealed ribbon even by HRTEM and electron diffraction pattern. The effective permeability at 1 kHz also exhibits high values above 20000 and the Curie temperature also shows high values above the onset temperature of crystallization corresponding to high thermal stability of soft magnetic properties. Besides, the (Fe0.8Co0.2)84B15Si1 and (Fe0.8Co0.2)85B14Si1 amorphous alloys exhibit good bending ductility even in the optimal annealed state. The corrosion resistance in 3.5 mass% NaCl aqueous solution is better than that for the commercial Fe-Si-B-C amorphous alloy. The first synthesis of the Fe-based amorphous alloy having simultaneously high Bs above 1.9 T, low Hc of about 2 A/m, high effective permeability, high Tc and good bending ductility is promising for future extension of amorphous alloys as engineering soft magnetic materials.

Soft magnetic Fe26.7Co26.7Ni26.6Si9B11 high entropy metallic glass with good bending ductility

New Fe26.7Co26.7Ni26.6Si9B11 high entropy metallic glass (HE-MG) with nanoscale FCC phase embedded in glass matrix was developed. The HE-MG shows superior soft magnetic properties (low coercivity (Hc) of 2A/m and high saturation magnetization (Bs) of 1.07 T) and good bending ductility even after stress-relief annealing. And high temperature annealing of the HE-MG can lead to the phase transition from FCC to BCC phase, and the crystallization phase of the glass matrix is also high entropy BCC phase instead of brittle intermetallic phase. This work will provide a new perspective to develop HE-MG with excellent comprehensive properties.

Excellent soft magnetic Fe-Co-B-based amorphous alloys with extremely high saturation magnetization above 1.85 T and low coercivity below 3 A/m

Abstract Extremely good soft magnetic properties of high saturation magnetization ( B s ) above 1.8 T and low coercivity ( H c ) below 5 A/m were obtained for (Fe 1- x Co x ) 83 B 16 Si 1 ( x = 0.1–0.3) amorphous ribbons annealed at the temperature between T x1 -120 K and T x1 -40 K. Here T x1 is the onset temperature of the first exothermic crystallization peak. The best characteristics were 1.86 T for B s and 3 A/m for H c at x = 0.2. There are no previous data on the melt-spun alloys with high B s above 1.8 T and low H c below 5 A/m and hence the present amorphous alloys are regarded as a novel good soft magnetic alloy with high B s comparable to Fe-Si steels. Curie temperature ( T c ) of the x = 0.2 alloy was above T x1 (708 K), implying high thermal stability of magnetic characteristics. The saturated magnetostriction for x = 0.2 was about 32 ppm and the effective permeability at 1 kHz showed as high as 1.6 × 10 4 . The high B s can be attributed to the low metalloid content containing mainly B element which suppresses effectively the reductions of B s and T c among metalloid elements, as well as the optimum Co/Fe content ratio with the maximum magnetic interaction in conjunction with maximum atomic volume. Moreover, these alloy ribbons exhibited good bending ductility even after optimum annealing treatment, in addition to high Vickers hardness of about 1000 and improved corrosion resistance comparing with the corresponding Co-free alloy. The excellent soft magnetic amorphous alloys are promising for further extension as engineering soft magnetic materials.

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.

Formation, magnetic properties and bending deformation of Fe-based amorphous alloy without metalloids

In this work, we synthesized a new Fe-based amorphous alloy without metalloids, X-ray diffractometer(XRD), differential scanning calorimeter (DSC), vibrating sample magnetometer(VSM) and scanning electron microscope(SEM) were adopted to study the formation, thermals stability, magnetic properties and bending ductility of (Fe0.52Co0.48-xNix)73Cr17Zr10 (x = 0.18,0.30) amorphous alloy ribbons. The amorphous alloys exhibit certain magnetic properties, through proper annealing conditions, The saturation magnetization(Ms) and coercivities (Hc) values of the annealed ribbons can reach up to 112.8A·m2·kg−1 and 6.6Oe, respectively. In additional, the as-spun and annealed alloy ribbons show good bending ductility, they will become promising functional/structural materials in the future.

SENNTIX-type amorphous alloys with high Bs and improved corrosion resistance

Abstract The magnetic, mechanical and corrosion properties were investigated for the SENNTIX-type Fe 84−x B 8.5 Si 4.5 P 3 (Nb 0.67 Cr 0.33 ) x alloys. The alloys show high saturation magnetization up to 1.53 T, low coercivity of 2.8–3.9 A/m and high effective permeability 11100–12900. In addition, the ribbons show good bending ductility even in the annealed state. By simultaneous addition of Cr and Nb to Fe-B-P-Si alloy, the corrosion potential increases nobler to the passive state. The corrosion resistance has been significantly improved compared with the (Cr, Nb)-free alloys, which is presumably due to the formation of (Cr, Nb)-rich passive film.

FeCo-based soft magnetic alloys with high Bs approaching 1.75 T and good bending ductility

Fe-rich amorphous alloys with FeCo contents above 85 at% were formed by partial replacement of Fe by Co in Fe-Si-B-P alloy system. The resulting alloys exhibit good soft magnetic properties and bending ductility after stress relief annealing. Moreover, the maximum magnetic flux density (Bs) approaches 1.75 T, which is higher than those for previous reported Fe-rich Fe-metalloid alloys. Thus, the partial substitution of Fe by Co caused both Curie temperature (TC) and Bs exceeding those for the Fe-Si-B-P alloys. Any compositional modification so as to raise TC was found to be effective for the further increase in the previous maximum value of Bs for the Fe-metalloid amorphous alloy system reported to date. Based on this concept, it is expected that further high Bs exceeding largely 1.75 T is obtained for Fe-based soft magnetic alloys with higher total ferromagnetic element content.

New Fe-based soft magnetic amorphous alloys with high saturation magnetization and good corrosion resistance for dust core application

Fe-rich amorphous dust core alloys with minor-addition of Mo and/or Cr were synthesized because of the industrial request of mass production of high efficient low core loss Fe-based dust cores. It was found that the present Fe-(Cr, Mo)-P-B-Si-(C) amorphous alloy ribbons exhibit good soft magnetic properties of above 1.5 T for saturation magnetization, below 10 A/m for coercivity and rather good corrosion resistance in 3%NaCl aqueous solution. Besides, the amorphous alloy ribbons exhibit good bending ductility in as-spun and optimally annealed states. It is noticed that these characteristics are much superior to those for commercial Fe-Cr-Nb-P-B-Si soft magnetic dust core alloy (SENNTIX). In addition, the annealing treatment was noticed to cause the improvement of corrosion resistance without detriment to bending ductility. The new Fe-based soft magnetic alloys with good combined characteristics are expected to be used as the basic material as high-efficient soft magnetic dust cores in a high frequency range.

Syntheses and Fundamental Properties of Fe-rich Metastable Phase Alloys with Saturation Magnetization Exceeding 1.9 T

A melt-spun Fe90Si5B5 alloy ribbon consists of bcc-Fe(Si) + Fe3B + amorphous phase and exhibits good bending ductility, high tensile fracture strength above 1000 MPa, high corrosion resistance and unique magnetic properties as exemplified for high saturation magnetization exceeding 1.9 T, moderately high initial permeability of about 150 and low coercivity of 745 A/m which are attractive for magnetic sensors utilizing a nearly constant high permeability with applied field up to coercivity. Besides, the tensile fracture strength and elongation increase significantly to 1286 MPa and 0.62%, respectively, after annealing for 900 s at 823 K. The Fe-Si-B alloy ribbons are attractive as a new type of sensor material with features of high bending ductility, high tensile strength and elongation, relatively good corrosion resistanceand unique soft magnetic properties with very high saturation magnetization.