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

A metallic article is fabricated by providing a die and a piece of a bulk-solidifying amorphous metallic alloy having a glass transition temperature. The bulk-solidifying amorphous metallic alloy is heated to a forming temperature of from about 0.75 Tg to about 1.2 Tg and forced into the die cavity at the forming temperature under an external pressure of from about 260 to about 40,000 pounds per square inch, thereby deforming the piece of the bulk-solidifying amorphous metallic alloy to a formed shape that fills the die cavity. Preferably, a pressure is applied to the piece of the bulk-solidifying amorphous metallic alloy as it is heated, and the heating rate is at least about 0.1° C. per second. The die may be a male die or a female die. When the die has a re-entrant comer therein, the formed shape of the bulk-solidifying amorphous metallic alloy is mechanically locked to the die.

Die-formed amorphous metallic articles and their fabrication

Solid die-cast articles are prepared from a charge of a bulk-solidifying amorphous alloy. The charge is heated to an injection temperature and injected into a die-casting mold. The charge is cooled at a rate, about 500° C. per second or less, such that its amorphous structure is retained in the solidified article.

Die casting of bulk-solidifying amorphous alloys

A reinforcement-containing metal-matrix composite material (20) is formed by dispersing pieces of reinforcement material (22) throughout a melt of a bulk-solidifying amorphous metal and solidifying the mixture at a sufficiently high rate that the solid metal matrix (24) is amorphous. Dispersing is typically accomplished either by melting the metal and mixing the pieces of reinforcement material (22) into the melt, or by providing a mass of pieces of the reinforcement material (22) and infiltration of the molten amorphous metal into the mass. The metal preferably has a composition of about that of a eutectic composition, and most preferably has a composition, in atomic percent, of from about 45 to about 67 percent total of zirconium plus titanium, from about 10 to about 35 percent beryllium, and from about 10 to about 38 percent total of copper plus nickel.

Amorphous metal/reinforcement composite material

The specific volumes of the Zr41.2Ti13.8CU12.5Ni10.0Be2.25 alloy as a function of temperature, T, are determined by employing an image digitizing technique and numerical calculation methods applied to the electrostatically levitated spherical alloy. The linear fitting of the volumes of the alloy in the liquid, V-l, glass, V-g, and crystalline V-c, states in the temperature ranges shown in parentheses are V-l(T) = 0.1583 + 8.877 x 10(-6)T(cm^(3)/g) (700-1300 K); V-g(T) = 0.1603 + 5.528 x 10^(-6)T (400-550 K); V-c(T) = 0.1583 + 6.211 x 10(-6)T(400-850 K). The average volume thermal expansion coefficients within the temperature ranges are determined to be 5.32, 3.39, and 3.83 x 10^(-5) (1/K) for the liquid, glass, and crystalline states, respectively.

/pdf/specific-volumes-of-the-zr-41-2-ti-13-8-cu-12-5-ni-10-0-be-mj2jx1axnx.pdf

Specific Volumes of the Zr(41.2)Ti(13.8)Cu(12.5)Ni(10.0)Be(22.5) Alloy in the Liquid, Glass, and Crystalline States

A process and apparatus for thermoplastic casting of a suitable glass forming alloy is provided. The method and apparatus comprising thermoplastically casting the alloy in either a continuous or batch process by maintaining the alloy at a temperature in a thermoplastic zone, which is below a temperature, Tnose, (where, the resistance to crystallizatioin is minimum) and above the glass transistion temperature, Tg, during the shaping or moulding step, followed by a quenching step where the item is cooled to the ambient temperature. A product formed according to the thermoplastic casting process is also provided.

Atakan Peker

Papers

Die-formed amorphous metallic articles and their fabrication

Die casting of bulk-solidifying amorphous alloys

Amorphous metal/reinforcement composite material

Specific Volumes of the Zr(41.2)Ti(13.8)Cu(12.5)Ni(10.0)Be(22.5) Alloy in the Liquid, Glass, and Crystalline States

Thermoplastic casting of amorphous alloys