https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Inoue-ActaMater00-Stabilization%20of%20metallic%20supercooled%20liquid%20and%20bulk%20amorphous%20alloys.pdf

Stabilization of metallic supercooled liquid and bulk amorphous alloys

Microstructures and properties of high-entropy alloys

Amorphous alloys were first developed over 40 years ago and found applications as magnetic core or reinforcement added to other materials. The scope of applications is limited due to the small thickness in the region of only tens of microns. The research effort in the past two decades, mainly pioneered by a Japanese- and a US-group of scientists, has substantially relaxed this size constrain. Some bulk metallic glasses can have tensile strength up to 3000 MPa with good corrosion resistance, reasonable toughness, low internal friction and good processability. Bulk metallic glasses are now being used in consumer electronic industries, sporting goods industries, etc. In this paper, the authors reviewed the recent development of new alloy systems of bulk metallic glasses. The properties and processing technologies relevant to the industrial applications of these alloys are also discussed here. The behaviors of bulk metallic glasses under extreme conditions such as high pressure and low temperature are especially addressed in this review. In order that the scope of applications can be broadened, the understanding of the glass-forming criteria is important for the design of new alloy systems and also the processing techniques.

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Shek-MaterSciEng04-Bulk%20Metallic%20Glasses.pdf

Bulk metallic glasses

Bulk metallic glasses (BMGs) have been classified according to the atomic size difference, heat of mixing (� H mix ) and period of the constituent elements in the periodic table. The BMGs discovered to date are classified into seven groups on the basis of a previous result by Inoue. The seven groups are as follows: (G-I) ETM/Ln-LTM/BM-Al/Ga, (G-II) ETM/Ln-LTM/BM-Metalloid, (G-III) Al/Ga-LTM/BMMetalloid, (G-IV) IIA-ETM/Ln-LTM/BM, (G-V) LTM/BM-Metalloid, (G-VI) ETM/Ln-LTM/BM and (G-VII) IIA-LTM/BM, where ETM, Ln, LTM, BM and IIA refer to early transition, lanthanide, late transition, group IIIB–IVB and group IIA-group metals, respectively. The main alloying element of ternary G-I, G-V and G-VII, ternary G-II and G-IV, and ternary G-VI BMGs is the largest, intermediate and smallest atomic radius compared to the other alloying elements, respectively. The main alloying element of ternary BMGs belonging to G-I, G-V, G-VI and G

Classification of Bulk Metallic Glasses by Atomic Size Difference, Heat of Mixing and Period of Constituent Elements and Its Application to Characterization of the Main Alloying Element

https://www.andrew.cmu.edu/user/dl0p/laughlin/pdf/PMS.pdf

Amorphous and nanocrystalline materials for applications as soft magnets

PROBLEM TO BE SOLVED: To provide a powder magnetic core of which core characteristics are improved, especially by introducing parameters of frequency and cumulation of particle diameters and increasing a filling factor of amorphous soft magnetic alloy powder, and to provide a manufacturing method thereof. SOLUTION: Frequency of the particle diameters in an cumulation range 10-90% is suppressed to be not higher than 8% by mixing 4 μm classified powder 5-50 mass% in reference powder (D50=12.25 μm) of amorphous soft magnetic alloy power, for example, mainly containing Fe and further containing at least two out of P, C, B, Si. As a result, the filling factor of the amorphous soft magnetic alloy powder with respect to the powder magnetic core can be increased as compared with the powder magnetic core containing only the reference powder, core loss can be reduced, and furthermore, magnetic permeability can be increased. COPYRIGHT: (C)2009,JPO&INPIT

Powder magnetic core, and manufacturing method thereof

New core (LiqualloyTM core) made of soft magnetic Fe-based glassy alloy powder was fabricated by the consolidation using an uni-axial mechanical press at room temperature. This new core has the constant relative permeability (μ') of about 60 up to 1 MHz and extremely low core loss blow 200kW/m3 at f=100kHz and Bm=0.1 T. The efficiency of the switching power supply (η) was improved by 2∼3% when the LiqualloyTM core was used instead of Fe-Al-Si core. The temperature rise near the LiqualloyTM core (ΔT) was also 10K lower than that of the Fe-Al-Si core. These excellent properties of the LiqualloyTM core are based on its extremely low hysteresis and eddy current losses. These low losses are originated from its good soft magnetic properties (Hc=2A/m) after annealing at relatively low temperature, its intrinsic hardness (Hv=1000) and high resistivitiy (ρ=160μΩcm).

Preparation of the Fe-based Glassy Alloy Powder Cores and their Applications

[Object] To provide in particular an Fe-based amorphous alloy powder which has a low glass transition temperature (Tg) and an excellent corrosion resistance and which is used for a dust core or a coil-embedded dust core, each having high magnetic characteristics. [Solution] An Fe-based amorphous alloy powder of the present invention has a composition represented by (Fe100-a-bc-x-y-z-tNiaSnbCrcPxCyBzSit)100-αMα. In this composition, 0 at%≤a≤10 at%, 0 at%≤b≤3 at%, 0 at%≤c≤6 at%, 6.8 at%≤x≤10.8 at%, 2.2 at%≤y≤9.8 at%, 0 at%≤z≤4.2 at%, and 0 at%≤t≤3.9 at% hold, a metal element M is at least one selected from the group consisting of Ti, Al, Mn, Zr, Hf, V, Nb, Ta, Mo, and W, and the addition amount α of the metal element M satisfies 0.04 wt%≤α≤0.6 wt%. Accordingly, besides a decrease of Tg, an excellent corrosion resistance and high magnetic characteristics can be obtained.

Fe-BASED AMORPHOUS ALLOY POWDER, DUST CORE USING THE Fe-BASED AMORPHOUS ALLOY POWDER, AND COIL-EMBEDDED DUST CORE

Nanocrystallization and magnetic properties of Fe56Co7Ni7Zr2M8B20(M = Nb or Ta) Glassy alloys

PROBLEM TO BE SOLVED: To provide a dust core which has a low coercive force and causes little core loss, and to provide a method of manufacturing the core. SOLUTION: The dust core is manufactured by mixing the powder of a metal-glass alloy containing Fe, Al, and at least one or more kinds of elements Q, selected from among P, C, Si, and B and having an amorphous phase as the main phase with an insulating material and molding the mixture by using a supercooling liquid, having a temperature interval ΔTx (ΔTx=Tx-Tg (where Tx and Tg respectively denotes the crystallization starting temperature and glass transition temperature)) of >=20 K. The method of manufacturing the core includes a powder manufacturing step of manufacturing the powder of the metal-glass alloy, a molding step of forming the precursor of the core by mixing the insulating material with the powder of the alloy and compression- molding the mixture, and a heat-treating step of removing the internal stresses of the precursor by heat-treating the precursor at a temperature between (Tg-170) K or higher and (Tg) K or lower.

Hisato Koshiba

Papers

Powder magnetic core, and manufacturing method thereof

Preparation of the Fe-based Glassy Alloy Powder Cores and their Applications

Fe-BASED AMORPHOUS ALLOY POWDER, DUST CORE USING THE Fe-BASED AMORPHOUS ALLOY POWDER, AND COIL-EMBEDDED DUST CORE

Nanocrystallization and magnetic properties of Fe56Co7Ni7Zr2M8B20(M = Nb or Ta) Glassy alloys

Dust core and its manufacturing method