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

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

The following article is based on the MRS Medal talk presented by William L. Johnson at the 1998 MRS Fall Meeting on December 2, 1998. The MRS Medal is awarded for a specific outstanding recent discovery or advancement that has a major impact on the progress of a materials-related field. Johnson received the honor for his development of bulk metallic glass-forming alloys, the fundamental understanding of the thermodynamics and kinetics that control glass formation and crystallization of glass-forming liquids, and the application of these materials in engineering.The development of bulk glass-forming metallic alloys has led to interesting advances in the science of liquid metals. This article begins with brief remarks about the history and background of the field, then follows with a discussion of multicomponent glass-forming alloys and deep eutectics, the chemical constitution of these new alloys, and how they differ from metallic glasses of a decade ago or earlier. Recent studies of deeply undercooled liquid alloys and the insights made possible by their exceptional stability with respect to crystallization will then be discussed. Advances in this area will be illustrated by several examples. The article then describes some of the physical and specific mechanical properties of bulk metallic glasses (BMGs), and concludes with some interesting potential applications.The first liquid-metal alloy vitrified by cooling from the molten state to the glass transition was Au-Si, as reported by Duwez at Caltech in 1960. Duwez made this discovery as a result of developing rapid quenching techniques for chilling metallic liquids at very high rates of 105–106 K/s.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0883769400053252

Bulk Glass-Forming Metallic Alloys: Science and Technology

The factors of the atomic size difference Delta and the enthalpy of mixing ΔH mιx of the multi-component alloys were summarized from the literatures. The formation zones of solid-solution phases, intermediate phases, and bulk metallic glasses were determined and the validity was verified by experimental results. For forming the solid solution, the alloys should have high entropy of mixing, lower Delta, and not too negative and positive enthalpy of mixing.

Solid‐Solution Phase Formation Rules for Multi‐component Alloys

We report on the properties of one example of a new family of metallic alloys which exhibit excellent glass forming ability. The critical cooling rate to retain the glassy phase is of the order of 10 K/s or less. Large samples in the form of rods ranging up to 14 mm in diameter have been prepared by casting in silica containers. The undercooled liquid alloy has been studied over a wide range of temperatures between the glass transition temperature and the thermodynamic melting point of the equilibrium crystalline alloy using scanning calorimetry. Crystallization of the material has been studied. Some characteristic properties of the new material are presented. The origins of exceptional glass forming ability of these new alloys are discussed.

/pdf/a-highly-processable-metallic-glass-zr41-2ti13-8cu12-5ni10-4oi7knbu3i.pdf

A highly processable metallic glass: Zr41.2Ti13.8Cu12.5Ni10.0Be22.5

Alloys which form metallic glass upon cooling below the glass transition temperature at a rate appreciably less than 10 6 K/s comprise beryllium in the range of from 5 to 52 atomic percent and at least one early transition metal in the range of from 30 to 75% and at least one late transition metal in the range of from 2 to 52% A preferred group of metallic glass alloys has the formula (Zr 1-X Ti X ) a (Cu 1-y Ni y ) b Be c  Generally, a is in the range from 30 to 75% and the lower limit increases with increasing x When x is in the range of from 0 to 015, b is in the range of from 5 to 52%, and c is in the range of from 6 to 47% When x is in the range of from 015 to 04, b is in the range of from 5 to 52%, and c is in the range of from 5 to 47% When x is in the range of from 04 to 06, b is in the range of from 5 to 52%, and c is in the range of from 5 to 47% When x is in the range of from 06 to 08, b is in the range of from 5 to 52%, and c is in the range of from 5 to 42% When x is in the range of from 08 to 1, b is in the range of from 5 to 52%, and c is in the range of from 5 to 30% Other elements may also be present in the alloys in varying proportions

Berylllium bearing amorphous metallic alloys formed by low cooling rates

Gold-based bulk metallic glass alloys based on Au-Cu-Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5 mm in the best glassformer. Au49Ag5.5Pd2.3Cu26.9Si16.3 has a liquidus temperature of 644 K, a glass transition temperature of 401 K, and a supercooled liquid region of 58 K. The Vickers hardness of the alloys in this system is similar to 350 Hv, twice that of conventional 18-karat crystalline gold alloys. This combination of properties makes the alloys attractive for many applications including electronic, medical, dental, surface coating, and jewelry.

/pdf/gold-based-bulk-metallic-glass-o3x3x0p2jq.pdf

Gold based bulk metallic glass

At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 103 K/s. One group of such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula: (ETM?1-x?Tix)aCub(Ni1-yCoy)c, wherein x is from 0.1 to 0.3, y?.?c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content.

METALLIC GLASS ALLOYS OF Zr, Ti, Cu AND Ni

A metal frame for electronic hardware and a method of manufacturing such a frame wherein at least a portion of the frame is made of bulk-solidifying amorphous alloys or bulk-solidifying amorphous alloy-composites is provided. The metal frames of the invention are preferably made of bulk-forming amorphous alloys or bulk-forming amorphous alloy-composites having an elastic limit for the metal frame of at least about 1.5%, and preferably greater than about 2.0%, a ΔTsc of more than 30° C., and at least one of the following properties: a hardness value of about 4 GPA or more, and preferably 5.5 GPA or more; a yield strength of about 2 GPa or more; a fracture toughness of about 10 ksi-sqrt(in) (sqrt:squre root) or more, and preferably 20 ksi sqrt(in) or more; and a density of at least 4.5 g/cc or more.

Atakan Peker

Papers

A highly processable metallic glass: Zr41.2Ti13.8Cu12.5Ni10.0Be22.5

Berylllium bearing amorphous metallic alloys formed by low cooling rates

Gold based bulk metallic glass

METALLIC GLASS ALLOYS OF Zr, Ti, Cu AND Ni

Metal frame for electronic hardware and flat panel displays