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

This paper deals with the formation and soft magnetic properties of Co(Fe)-M-B (M = transition Metals) glassy alloys in thin sheet and bulk ring forms prepared by single role melt spinning and copper mold casting methods. This multicomponent system was found to exhibit a distinct glass transition and a wide supercooled liquid region (ΔT x ) exceeding 70 K before crystallization. The high thermal stability of the supercooled liquid has enabled us to produce the bulk glassy alloys. The Co-Fe-Ta-B alloy samples with a ring form of Φ7 mm x Φ3 mm x t 1 mm consist of a single glassy phase. These bulk amorphous samples exhibit excellent soft magnetic properties, which are nearly the same as those of the corresponding melt-spun glassy thin sheets: the coercivity (H c ) and saturation magnetic flux density (B s ) are 0.25 A/m and 0.49 T, respectively. These good soft magnetic properties suggest structural homogeneity resulting from its high glass-forming ability. The excellent soft magnetic properties are useful for industrial application.

https://www.jstage.jst.go.jp/article/matertrans/42/12/42_12_2572/_pdf

Preparation and Magnetic Properties of Co-based Bulk Glassy Alloys

PURPOSE: A noncrystalline soft magnetic alloy powder is provided which has high saturated magnetization and low core loss and is manufactured in a near-spherical shape by water spraying, and dust core and electric wave absorber using the same are provided. CONSTITUTION: In a noncrystalline soft magnetic alloy powder that is powder formed in an approximately spherical shape by water spraying, the noncrystalline soft magnetic alloy powder comprises Fe as a principal component and at least one or more of P, C and B and is formed in an amorphous phase in which a temperature interval (ΔTx) of supercooling liquid represented as ΔTx=Tx-Tg is more than or equal to 20 K, where Tx and Tg respectively denote the crystallization starting temperature and glass transition temperature. The dust core is manufactured by mixing a plural or one of the noncrystalline soft magnetic alloy powder containing Fe as a principal component and at least one or more elements selected from among P, C and B and having an amorphous phase as the main phase with insulating material and lubricating agent and molding the mixture, wherein the insulating material is used as a binder for solidifying the mixture during molding of the mixture.

Noncrystalline soft magnetic alloy powder, and dust core and electric wave absorber using the same

The effect of the addition of the transitional metal Mo, on the glass-forming ability, mechanical strength and magnetic properties of Fe 78-x Mo x Ga 2 P 12 C 4 B 4 glassy alloys was investigated. The addition of 4 to 6 at%Mo was found to be effective for the extension of the supercooled liquid region (ΔT x ) defined by the difference between the glass transition temperature (T g ) and crystallization temperature (T x ). The ΔT x value is 30K for the Fe 78 Ga 2 P 12 C 4 B 4 alloy and increases to 60K for the 4 at%Mo alloy. These glassy ribbon alloys exhibit good soft magnetic properties of 1.13 to 1.34 T for saturation magnetization and 2.2 to 3.8 A/m for coercive force. Based on the large ΔT x values, we tried to prepare bulk glassy Fe 74 Mo 4 Ga 2 P 12 C 4 B 4 rods in a cylindrical form with different diameters. The glassy single phase was obtained in the diameter range of 1.0 to 2.0 mm. These bulk glassy alloys also exhibit high saturation magnetizations of about 1.20 T as well as a high compressive strength of 2685 MPa.

High Strength and Good Soft Magnetic Properties of Bulk Glassy Fe–Mo–Ga–P–C–B Alloys with High Glass-Forming Ability

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S194642740017589X

Synthesis and Properties of Ferromagnetic Bulk Amorphous Alloys

Local atomic structures in amorphous Fe 70 M 10 B 20 (M = Cr, W, Nb, Zr and Hf) alloys with different ΔT x values were studied by the ordinary X-ray diffraction, anomalous X-ray scattering and EXAFS methods. Their local the atomic structures basically resemble each other, i.e. a random network structure of triangular prisms. Only difference in local atomic structure is a shape of the local structural unit. In the amorphous alloys containing M elements larger than Fe atoms, the prisms show distorted shapes due to a size difference Δr between M and Fe. A linear relation between Δr and ΔT x , and a comparison of their crystallization processes suggest us that their thermal stability is attributed to difficulty in rearranging the irregular structural units because of a non-zero Ar value.

Hisato Koshiba

Papers

Preparation and Magnetic Properties of Co-based Bulk Glassy Alloys

Noncrystalline soft magnetic alloy powder, and dust core and electric wave absorber using the same

High Strength and Good Soft Magnetic Properties of Bulk Glassy Fe–Mo–Ga–P–C–B Alloys with High Glass-Forming Ability

Synthesis and Properties of Ferromagnetic Bulk Amorphous Alloys

Structural study of amorphous FE70M10B20(M = Cr, W, Nb, Zr and Hf) alloys by X-ray diffraction