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

An iron-based soft magnetic alloy with which a low core loss and high direct-current bias characteristics can be obtained; and a dust core formed using the iron-based soft magnetic alloy. The iron-based soft magnetic alloy is characterized by comprising iron and element R, the element R being at least one of P, C, B, and Si. The alloy is further characterized in that the difference in precipitation temperature between an α-Fe crystal phase and an iron compound is 20oC or more, and that the alloy is constituted of a mixed-phase structure composed of an amorphous phase and the α-Fe crystal phase, the α-Fe crystal phase having a crystallite diameter of 50 nm or smaller, and the volume proportion of the α-Fe crystal phase being not higher than 40% of the total. The alloy may be represented by the empirical formula Fe 100-x-u J x R u , wherein element J is at least one of Cr, Co, Ni, and Nb, 0 at.%≤x≤6 at.%, 17 at.%≤u≤25 at.%, and 17 at.%≤x+u≤27.1 at.%.

Iron-based soft magnetic alloy and dust core comprising the iron-based soft magnetic alloy

The primary metastable phase in the Fe70Nb10B20 amorphous alloy is the complex fcc Fe23B6 phase with a large lattice parameter The atomic site of Nb atoms in this metastable phase was determined by the anomalous X-ray scattering (AXS) method Nb atoms in the metastable phase located at the similar position expected in the local structural unit in the amorphous state Thus, the precipitation of the metastable phase does not require long-distance diffusion of Nb atoms in the amorphous matrix

Determination of atomic sites of Nb dissolved in metastable Fe23B6 phase

New Fe-based and Co-based amorphous alloys with a high B concentration of 30 at% were formed in the (Fe,Co,Ni)/sub 62/Nb/sub 8/B/sub 30/ system. The amorphous alloys exhibit a wide supercooled liquid region (/spl Delta/T/sub x/) above 80 K before crystallization in the range of 5 to 40% Co and 0 to 10% Ni and the largest /spl Delta/T/sub x/ is 87 K for Fe/sub 52/Co/sub 10/Nb/sub 8/B/sub 30/. The Fe/sub 62-x/Co/sub x/Nb/sub 8/B/sub 30/ alloys exhibit good soft magnetic properties i.e., low coercive force (H/sub c/) of 2-3 A/m, high effective permeability (/spl mu//sub e/) of 20000-30000 at 1 kHz and low saturated magnetostriction (/spl lambda//sub s/) of 2-8/spl times/10 d. The high /spl mu//sub e/ characteristics are maintained in a higher frequency range and the highest /spl mu//sub e/ at 1 kHz is 7500 for Co/sub 40/Fe/sub 22/Nb/sub 8/B/sub 30/ with a high resistivity of 237 /spl mu//spl Omega/ cm. The finding of the (Fe,Co)/sub 62/Nb/sub 8/B/sub 30/ amorphous alloys exhibiting large /spl Delta/T/sub x/, good high-frequency permeability and high resistivity is encouraging the future development as a new soft magnetic materials.

High-frequency permeability characteristics of Fe- and Co-based amorphous alloys with high B concentrations

Atomic structures in the amorphous Fe 70 M 10 B 20 (M = Zr, Nb and Cr) alloys with different ΔT x values were studied by the anomalous X-ray scattering method. Their basic structural features resemble each other except a shape of a triangular prism as a local structural unit. The prism is slightly distorted in the amorphous Fe 70 M 10 B 20 (M = Zr and Nb) alloys because a part of Fe atoms at the vertices are replaced by the M elements. The larger the size difference between M and Fe is, the larger the ΔT x value becomes. This tendency and the observations of the crystallization process by the differential scanning calorimetry and X-ray diffraction measurements indicate us a close relationship between thermal stability of the amorphous state and the shape of the prism in the amorphous Fe 70 M 10 B 20 alloy.

Retraction: Anomalous X-ray Scattering Study of Amorphous Fe 70 M 10 B 20 (M = Zr, Nb, and Cr) Alloys

PROBLEM TO BE SOLVED: To provide an amorphous soft magnetic alloy which has excellent soft magnetic properties, and has little deterioration in magnetic properties even when used as a magnetic core or the like. SOLUTION: The amorphous soft magnetic alloy having a structure in which ΔTx is >=20 K, having an amorphous phase as a main phase, and satisfying the following compositional formulae of (1) to (4) is adopted; (1) Fe100-x-y-z-w-tAlxPyCzBwXt; (2) (Fe1-aTa)100-x-y-z-w-tAlxPyCzBwXt; (3) Fe100-x-y-z-w-tAlx(P1-bSib)vCzBwXt; and (4) (Fe1-aTa)100-x-y-z-w-tAlx(P1-bSib)vCzBwXt. The alloy contains Fe alone or Fe and an element T by 70 to 79 atomic %, Al by 0 to 10 atomic % and P, C, B and (Si) by 11 go 30 atomic %, so that its saturation magnetization reaches 180×10-6 Wb.m/kg or higher, and the amorphous alloy exhibiting excellent soft magnetic properties can be composed.

Hisato Koshiba

Papers

Iron-based soft magnetic alloy and dust core comprising the iron-based soft magnetic alloy

Determination of atomic sites of Nb dissolved in metastable Fe23B6 phase

High-frequency permeability characteristics of Fe- and Co-based amorphous alloys with high B concentrations

Retraction: Anomalous X-ray Scattering Study of Amorphous Fe 70 M 10 B 20 (M = Zr, Nb, and Cr) Alloys

Amorphous soft magnetic alloy