Chang Chuntao

Inoue Akihisa

Kubota Takeshi

Makabe Masahiro

Makino Akihiro

MATERIALS TRANSACTIONS

Makino, Akihiro

Kubota, Takeshi

Chang, Chuntao

Makabe, Masahiro

Inoue, Akihisa

Tohoku University Repository (TOUR) / 東北大学機関リポジトリ

FeSiBP bulk metallic glasses with unusualcombination of high magnetization and highglass-forming ability著者 Makino Akihiro, Kubota Takeshi, Chang Chuntao,Makabe Masahiro, Inoue Akihisajournal orpublication titleMaterials Transactionsvolume 48number 11page range 3024-3027year 2007URL http://hdl.handle.net/10097/52350FeSiBP Bulk Metallic Glasses with Unusual Combinationof High Magnetization and High Glass-Forming AbilityAkihiro Makino1, Takeshi Kubota1, Chuntao Chang1, Masahiro Makabe1;* and Akihisa Inoue21Institute for Materials research, Tohoku University, Sendai 980-8577, Japan2Tohoku University, Sendai 980-8577, JapanAmong many kinds of bulk metallic glasses (BMGs), Fe-based BMGs with good magnetic properties, high strength and low materials costshould have great potential for wide variety of applications. However, the glass-forming metal elements such as Al, Ga, Nb, Mo, Y and so forthin the Fe-based BMGs significantly decrease saturation magnetization (Js) which is a essential property as soft magnetic materials and alsoincrease the material cost.The coexistence of high Fe content and high glass-forming ability (GFA) has been earnestly desired from academia to industry.We report anovel Fe76Si9B10P5 (at%) bulk metallic glass with unusual combination of high Js of 1.51 T due to high Fe content and high GFA leading to aglassy rod with a diameter of 2.5mm despite not-containing any glass-forming metal elements. This alloy composed of familiar and low-pricedelements, also exhibiting very excellent magnetic softness and rather high strength, has a great advantage for engineering and industry, and thusshould make a contribution to conservation of earth resources and environment through energy saving.[doi:10.2320/matertrans.MRP2007198](Received August 10, 2007; Accepted September 7, 2007; Published October 18, 2007)Keywords: soft magnetic material, Metallic glass, high magnetization, grass-forming ability1. IntroductionFe-metalloid (B, C, Si, P)-based ferromagnetic bulkmetallic glasses (BMGs) containing glass-forming metalelements such as Al, Ga, Nb, Mo, Y and so forth have beendeveloped.1–6) These alloys have a GFA leading to theformation of BMG rods with diameters of mm-order preparedby Cu-mold casting with much lower cooling rates than thatof melt-spinning used for the production of the Fe-metalloid-based amorphous alloy ribbons with a thickness of less thanabout 50 mm without glass transition. The development ofBMGs overcame the great disadvantage of the melt-spunamorphous ribbons. However, the glass-forming metalelements in BMGs result in a remarkable decrease insaturation magnetization (Js) from 1.5–1.6 T of the repre-sentative Fe-Si-B amorphous alloys widely utilized byindustries7) to less than about 1.3 T. The magnetic elementssuch as Co and Ni also have some beneficial effects on theGFA in most cases,8,9) however, the addition of theseelements to Fe-based BMGs significantly decreases Js inthe same manner as the glass-forming elements; thesubstitution of Co for Fe at 50 at% in (Fe0:75Si0:10B0:15)96Nb4significantly increases the critical rod-size of 1.5mm to 5mmin diameter, which is the largest size among the soft magneticBMGs produced by Cu-mold casting, however, rapidlydecreases to 1.1 T.8) The low Js of the BMGs is a greatdisadvantage as soft magnetic materials. In addition, thesemetal elements are rare and expensive, and Al, Nb, Mo and Yalso decrease the productivity due to their easy oxidation. Itshould be, thus, better to avoid the use of these metalelements for high Js as well as conservation of earthresources and low material cost. Therefore, the developmentof Fe-based BMGs without any metal elements other than Feand with relatively high Fe content have been desired for thelast one decade, however, has been left unsolved matter overmany years. We report a novel Fe76Si9B10P5 bulk metallicglass with unusual combination of high Js of 1.51 T due tohigh Fe content and high GFA leading to a glassy rod with adiameter of 2.5mm despite not-containing any glass-formingmetal elements.2. ExperimentalFe-Si-B-(P) ingots were prepared by induction melting themixture of pure metals of Fe (99.98mass%), pre-melted Fe-P(99.9mass%), and pure metalloid of crystal B (99.5mass%)and Si (99.999mass%) in an argon atmosphere. The alloycompositions represent nominal atomic percent. Amorphousor glassy alloys were produced in a ribbon form by the singleroller melt-spinning method and in rod forms by the Cu-moldcasting method. The as-spun and as-cast structures wereexamined by X-ray diffraction (XRD). The glass transitiontemperature (T g) and crystallization temperature (T x) wereestimated by a differential scanning calorimetry (DSC) at aheating rate of 0.67K/s and the liquidus temperature (T l)was also estimated by a thermogravimetry differentialthermal analyzer at a cooling rate of 0.17K/s. The density() was measured by the Archimedean method using apycnometer with Helium gas at 298K. Cross section of bulkrod with 2.5mm in diameter was etched for 30 s at roomtemperature in a solution of 1% hydrofluoric acid and 99%distilled water, and was observed by an optical microscopy.Js was measured under an applied field of 800 kA/m with avibrating sample magnetometer. The coercivity (Hc) wasmeasured under a field of 1 kA/mwith a DCB-H loop tracer.The specimens for coercivity measurement were heatedunder a vacuum atmosphere of less than 2 104 Pa at aheating rate of 0.67K/s and isothermal annealed at prescri-bed temperature for 0.6 or 7.2 ks, and then cooled to 295Kby the furnace cooling. Mechanical properties of Young’smodulus, compressive fracture strength, elastic strain, and*Graduate Student, Tohoku University. Present address: Makabe R&D Co.ltd., Sendai 983-0036, JapanMaterials Transactions, Vol. 48, No. 11 (2007) pp. 3024 to 3027#2007 The Japan Institute of Metals RAPID PUBLICATIONfracture strain were measured with an Instron testingmachine. The specimen dimension was 1.5mm in diameterand 3mm in length, and the strain rate was 5:0 104 s1.The characteristics of the fractured surface was studied byscanning electron microscopy (SEM). All the measurementswere carried out at room temperature.3. Results and DiscussionFigure 1 shows (a) the compositional dependence of as-quenched structure and supercooled liquid region (T x) formelt-spun alloys and (b) the critical rod-diameter producedby Cu-mold casting in Fe76(SixByPz)24 (xþ yþ z ¼ 1) alloysystem, respectively. The number in Fig. 1(a) represents thetemperature interval (T x), known to be one of the indicatorsfor GFA,10) between T g and T x. In Fig. 1(a) and 1(b),‘‘glassy’’ and ‘‘amorphous’’ alloys are distinguished by thepresence of glass transition. An amorphous phase wasobserved in a wide compositional range except higher Si, Band P contents than around 8%. Obvious glass transition wasobserved at the limited quaternary compositions in theamorphous-forming range and the large T x of over 40K isobserved in the range of x ¼ 0:3{0:5, y ¼ 0:2{0:5 andz ¼ 0:2{0:4. The largest T x is 52K for Fe76Si9:6B9:6P4:8and Fe76Si9B10P5. The rod with a diameter of 2.5mm wasobtained for the above mentioned alloys and Fe76Si7:2B12P4:8alloy, as shown in Fig. 1(b). Comparing Fig. 1(a) andFig. 1(b), it can be noted that critical diameter (Dcr)coincides with T x.Figure 2 shows (a) the optical micrograph and (b) theXRD pattern taken from the cross section of the as-castFe76Si9B10P5 rod with a diameter of 2.5mm. The XRDpattern reveals only typical halos, and no peaks correspond-ing to crystalline phases are visible. It is thus to be noticedthat a single glassy phase is formed in the diameter range upto 2.5mm.It is important in applications as engineering materials toclarify the magnetic and mechanical properties of the Fe-metalloids BMGs. The Hc of Fe76Si9B10P5 glassy alloy withT x of 52K and Fe76Si9B15 amorphous alloy without glasstransition as a function of annealing temperature is shown inFig. 3. The extremely low Hc of 0.8 A/m was obtained for0.6 ks at 748K for the glassy alloy. TheHc of the Fe76Si9B15amorphous alloy reaches a minimum value of 8.0A/m at653K and rapidly increases with increasing annealingtemperature above 653K, even though an amorphousstructure should remain in the temperature range, which isconsiderably lower than the crystallization temperature of841K. On the other hands, theHc of the Fe76Si9B10P5 glassyalloy reaches a minimum value of 0.8A/m at 748K, 10 timessmaller than the minimum Hc of 8.0 A/m for the amorphousalloy, and then slightly increases to 1.4 A/m at 773K justbelow the glass transition temperature of 780K. The  in as-quenched state was 7111 kg/m3 for the Fe76Si9B15 amor-phous alloy and 7054 kg/m3 for the glassy alloy. The  ofFig. 1 The compositional dependence of as-quenched structure, super-cooled liquid region (T x) for melt-spun alloys (a), and the critical rod-diameter (Dcr) produced by Cu-mold casting in Fe76(SixByPz)24(xþ yþ z ¼ 1) alloy system.Fig. 2 The optical micrograph (a) and the X-ray diffraction pattern (b)taken from the cross section of the as-cast Fe76Si9B10P5 rod with adiameter of 2.5mm.Fig. 3 The coercivity (Hc) of Fe76Si9B10P5 glassy alloy and Fe76Si9B15amorphous alloy as a function of annealing temperature.FeSiBP Bulk Metallic Glasses with Unusual Combination of High Magnetization and High Glass-Forming Ability 3025the glassy alloy significantly increases from 7054 kg/m3 to7207 kg/m3 by 2.17% upon the optimum annealing at 748K.This change is considered to originate from the glasstransition from the as-quenched amorphous phase with someinhomogeneity to a glassy phase with a higher degree ofatomic density of dense random packed structure. On thecontrary, the  of the amorphous alloy little changes by0.22% with annealing because of lack of glass transition.Considering the minimum values of Hc and the annealedstructure for the alloys, as described above, the extremely lowHc of 0.8 A/m for the glassy alloy can be explained as due tothe dense packed glassy structure. Taking account of thedifference in the optimum annealing temperature for Hc,748K for the glassy alloy and 653K for the amorphous alloy,we can see that the Fe76Si9B10P5 glassy alloy exhibits thehigher thermal stability of magnetic softness, which shouldindicate the higher stability of the glassy phase than theamorphous phase.11,12)Figure 4 shows the compressive stress-strain curve (a), andSEM micrographs revealing the compressive fracture surface(b) and shear bands on the specimen surface (c) of theFe76Si9B10P5 BMG with a diameter of 1.5mm, respectively.It can be seen that the specimen shows an initial elasticdeformation behavior with an elastic strain of 1.9%, thenbegins to yield at about 3.3 GPa, followed by some plasticdeformation of 0.7% before fracture. The yield stress issimilar to the Fe-based BMGs with the glass-formingelements.13,14) The measured Young modulus is 175GPa.SEM observations show that the fracture under compressionoccurs in a shear mode. On the specimen surfaces, it is notedthat many localized shear bands near the fracture plane wereobserved, as shown in Fig. 4(c). The shear bands have arelatively high density near the fracture plane. The activationof the shear bands should be a direct evidence for thecompressive plasticity of the Fe76Si9B10P5 BMG.Table 1 summarizes T g, T x, Dcr, T x, T g=T l,  andmagnetic properties (Js, Hc) for the Fe76Si9B10P5 BMG andthe typical Fe-based ferromagnetic BMGs previously report-ed.1,2,6,15–18) Here, T x, T g=T l19) and  (¼ T x=ðT g þ T lÞ)20)are adopted as the parameters, and the larger all theparameters, the higher is the GFA. The Fe76Si9B10P5 BMGhas the relatively high T x of 52K, comparable to the otherBMGs, and higher T g=T l of 0.62 and  of 0.41 than those ofthe other Fe-based BMGs, which are probably one of thereasons for the high GFA of the Fe76Si9B10P5 BMG leadingto the 2.5mm-diameter specimen.The Fe76Si9B10P5 BMG exhibits the highest Js of 1.51 Tamong the previously reported Fe-based BMGs due to thehigh Fe content of 76% and without any metal elementsexcept Fe as well as high GFA leading to the 2.5mm-diameter specimen.The P-added Fe-based amorphous and glassy alloys havebeen investigated for four decades ago.21–25) Fe80P13C725)alloys for ternary alloy and Fe-P-B-Si alloy system2) forFig. 4 The compressive stress-strain curve (a), the SEMmicrograph revealing the compressive fracture surface (b) and shear bands on thespecimen surface (c) of the as-cast Fe76Si9B10P5 BMG with a diameter of 1.5mm.3026 A. Makino, T. Kubota, C. Chang, M. Makabe and A. Inouequaternary alloy exhibit the glass transition were reported.However, bulk glassy rod specimen with over 0.5mm of adiameter have been not yet found, even though T x of 36Kwas obtained for Fe80P12B4Si4.2) Therefore, we can say thatthis discovery is the first achievement for simultaneousrealization of high Js and high GFA in Fe-based BMGs. Inaddition, the BMG is composed of 89.17mass%Fe and smallamounts of metalloid elements of Si, B and P. The elements,Fe, Si and P, are the constituent elements in pig-ironproduced by the reduction of iron ores typically in a blastfurnace. The low-priced Fe-Si and Fe-P ferroalloys are inmass production, thus, there is no restriction in available rawmaterials. Therefore, the FeSiBP alloy offers great advan-tages of much lower material cost for engineering andindustry, which should make a contribution to conservationof earth resources and environment, and should improveenergy saving due to the excellent magnetic softness.4. Conclusions(1) The large T x of over 40K is observed in the rangeof x ¼ 0:3{0:5, y ¼ 0:2{0:5 and z ¼ 0:2{0:4 forFe76(SixByPz)24 (xþ yþ z ¼ 1) alloy system. Thelargest T x is 52K for Fe76Si9:6B9:6P4:8 andFe76Si9B10P5.(2) Fe76Si9:6B9:6P4:8, Fe76Si9B10P5 and Fe76Si7:2B12P4:8alloys have high GFA leading to a glassy rod with adiameter of 2.5mm despite not-containing any glass-forming metal elements.(3) The higher Js of 1.51 T than those of the previouslyreported Fe-based BMGs was obtained forFe76Si9B10P5 alloy due to the high Fe content of 76%and without any metal elements except Fe.(4) The extremely lowHc of 0.8 A/m and the high strengthof 3.3 GPa and the plastic strain to final failure of 0.7%were obtained for Fe76Si9B10P5.AcknowledgementsThis work was supported by a Grant-in-Aid for ScientificResearch on Priority Areas, ‘‘Materials Science of BulkMetallic Glasses’’, from the Ministry of Education, Science,Sports and Culture of Japan.REFERENCES1) A. Inoue and B. L. Shen: Mater. Sci. Eng. A375–377 (2004) 302–306.2) A. Inoue and R. E. Park: Mater. Trans. JIM 37 (1996) 1715–1721.3) T. Mizushima, K. Ikarashi, A. Makino and A. Inoue: IEEE Trans. Mag.35 (1999) 3361–3363.4) H. Koshiba, A. Inoue and A. Makino: J. Appl. Phys. 85 (1999) 5136–5138.5) A. Makino, A. Inoue and T. Mizushima: Mater. Trans. JIM 41 (2000)1471–1477.6) B. L. Shen, M. Akiba and A. Inoue: Phys. Rev. B 73 (2006) 104204-1–104204-6.7) Metglas, http://www.metglas.com/8) A. Inoue, B. L. Shen and C. T. Chang: Acta Mater. 52 (2004) 4093–4099.9) C. T. Chang, B. L. Shen and A. Inoue: Appl. Phys. Lett. 89 (2006)051912-1–051912-3.10) P. R. Okamoto, N. Q. Lam and L. E. Rein: in solid state physics 52, ed.by H. Ehrenreich and F. Spaepen, (Academic Press, San Diego, 1999)pp. 2–133.11) T. Bitoh, A. Makino and A. Inoue: Mater. Trans. 44 (2003) 2020–2024.12) T. Bitoh, A. Makino and A. Inoue: J. Appl. Phys. 99 (2006) 08F102-1–08F102-3.13) A. Inoue, B. L. Shen, A. V. Yavari and A. L. Greer: J. Mater. Res. 18(2000) 1487–1492.14) M. Stoica, J. Eckert, S. Roth, A. R. Yavari and L. Schultz: J. Alloy.Comp. 434–435 (2007) 171–175.15) A. Inoue, Y. Shinohara and J. S. Gook: Mater. Trans. JIM 36 (1995)1427–1433.16) A. Inoue, A. Takeuchi, T. Zhang, A. Murakami and A. Makino: IEEETrans. Mag. 32 (1996) 4866–4871.17) T. Zhang and A. Inoue: Mater. Trans. 42 (2001) 1015–1018.18) D. D. Song, J.-H. Kim, E. Fleury, W. T. Kim and D. H. Kim: J. AlloysComp. 389 (2005) 159–164.19) Z. P. Lu, H. Tan, Y. Li and S. C. Ng: Scr. Mater. 42 (2000) 667–673.20) Z. P. Lu and C. T. Liu: Acta Mater. 50 (2002) 3501–3512.21) N. S. Naka, M. Mitera and T. Masumoto: Proc. 3rd Intern. Conf. OnRapidly Quenched Metals, Brighton, 2 (1978) pp. 164–171.22) M. Mitera, M. Naka, T. Masumoto, N. Kazama and K.Watanabe: Phys.Stat. Sol. (a)49 (1978) K163–K166.23) M. Naka and T. Masumoto: Sci. Rep. RITU A27 (1979) 118–126.24) M. Ohnuma, O. Sasaki, H. Kuwano, S. Katano, Y. Morii, S. Funahashi,H. R. Child and Y. Hamaguchi: Mater. Trans. JIM 34 (1993) 874–881.25) B. L. Shen and A. Inoue: J. Mater. Sci. Let. 22 (2003) 857–859.Table 1 The glass transition temperature (T g), the crystallization temperature (T x), the critical diameter (Dcr), the parameters (T x,T g=T l and ), and magnetic properties (Js,Hc) for the Fe76Si9B10P5 and the typical Fe-based ferromagnetic BMGs previously reported.composition T g (K) T x (K) T x (K) T g=T l  Js (T) Hc (A/m) Dcr (mm)Fe76Si9B10P5 780 832 52 0.62 0.41 1.51 0.8 2.5(Fe0:75Si0:1B0:15)96Nb4 835 885 50 0.61 0.40 1.40 2.9 1.5Fe74Al4Ga2P12B4Si4 733 782 49 — — 1.14 6.4 —Fe73Al5Ga2P11C5B4 732 785 53 — — 1.29 6.3 1Fe72Al5Ga2P10C6B4Si1 732 785 53 — — 1.14 2.8 2Fe76Mo2Ga2P10C4B4Si2 736 788 52 0.59 0.40 1.32 2.9 2Fe30Co30Ni15Si8B17 780 834 54 — — 0.92 3.4 1.2Fe74Nb6Y3B17 831 789 48 — — 0.81 15 2FeSiBP Bulk Metallic Glasses with Unusual Combination of High Magnetization and High Glass-Forming Ability 3027

FeSiBP bulk metallic glasses with unusual combination of high magnetization and high glass-forming ability

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FeSiBP bulk metallic glasses with unusual combination of high magnetization and high glass-forming ability

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