JP2017043850A - Amorphous alloy powder feedstock processing process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing an amorphous alloy powder having desirable mechanical properties at low production cost.SOLUTION: In a method of producing feedstock comprising a bulk metallic glass (BMG), the powder has elements of the BMG, and the elements in the powder have the same weight percentage as in the BMG. The powder is compacted in a sheath to obtain the feedstock. The powder and the sheath together have elements of the BMG, and the elements in the powder have the same weight percentage as in the BMG.SELECTED DRAWING: None

Description

  Most metal alloys used today are processed by solidification casting, at least in the early stages. The metal alloy is melted and poured into a metal or ceramic mold where it solidifies. The mold is removed and the cast metal piece can be used as it is or for further processing. The as-cast structure of most materials created during solidification and cooling depends on the cooling rate. There are no general rules regarding the nature of the mutation, but for the most part its structure only changes gradually with changes in cooling rate. On the other hand, for bulk-solidifying amorphous alloys, the change between the amorphous state created by relatively rapid cooling and the crystalline state created by relatively slow cooling is a type change, not a degree, and The two states have distinctly different characteristics.

  Bulk solidified amorphous alloys, or bulk metallic glass (“BMG”), is a recently developed class of metallic materials. These alloys can be solidified and cooled at a relatively moderate rate, and they maintain an amorphous, amorphous (ie, vitreous) state at room temperature. This amorphous state can be extremely advantageous for specific applications. If the cooling rate is not fast enough, crystals may form inside the alloy during cooling, so that the benefits of the amorphous state are partially or completely lost. For example, one of the risks associated with the fabrication of bulk amorphous alloy parts is partial crystallization, either due to slow cooling or impurities in the raw material.

Bulk solidified amorphous alloys are made of various metal systems. These alloys are generally prepared by quenching from a temperature above the melting temperature to ambient temperature. In general, to achieve an amorphous structure, a high cooling rate, such as about 10 ⁵ ° C / second, is required. The lowest rate at which a bulk solidified alloy can be cooled to avoid crystallization and thereby build and maintain an amorphous structure during cooling is referred to as the “critical cooling rate” for that alloy. In order to achieve a cooling rate faster than this critical cooling rate, heat must be extracted from the sample. Thus, the thickness of an article made from an amorphous alloy is often of a limited dimension, commonly referred to as the “critical (cast) thickness”. The critical thickness of the amorphous alloy can be obtained by heat flow calculation taking into account the critical cooling rate.

  Until the early 90s, the workability of amorphous alloys was very limited, and readily available amorphous alloys are in the form of powders or ultrathin foils or strips having a critical thickness of less than 100 micrometers It was only. A class of amorphous alloys based primarily on Zr and Ti alloy systems was developed in the 90s, and since then more amorphous alloy systems based on various elements have been developed. Because these families of alloys have a much slower critical cooling rate of less than 10 ° C./second, they have a critical casting thickness that is much greater than their previous counterparts. However, little is shown regarding methods for utilizing these alloy systems and / or forming into structural components such as components in consumer electronics. Specifically, for high aspect ratio products (eg, thin sheets) or three-dimensional hollow products, existing molding or processing methods often result in high production costs. Furthermore, these existing methods can often suffer from the disadvantage of producing products that have lost many of the desirable mechanical properties found in amorphous alloys.

  Described herein is a method for producing a raw material containing BMG. Because of this raw material, the powder is compacted. This powder has the elements of BMG, and the elements of the powder have the same weight percentage as that of BMG.

  Described herein is a method for producing a raw material containing BMG. Because of this raw material, the powder is consolidated in the sheath. The powder and sheath together have an element of BMG, and the element of the powder has the same weight percent as that of BMG.

FIG. 3 is a temperature-viscosity diagram of an exemplary bulk solidified amorphous alloy.

1 is a schematic diagram of a time-temperature-transformation (T) diagram for an exemplary bulk solidified amorphous alloy. FIG.

It is a figure which compacts powder.

It is a figure which compacts powder in a sheath.

  All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

  The articles “a” and “an” are used herein to refer to one or more (ie, at least one) grammatical objects of the article. By way of example, “a polymer resin” means one polymer resin or more than one polymer resin. Any ranges set forth herein are inclusive. The terms “substantially” and “about” as used throughout this specification are used to describe and explain minor variations. For example, the terms are ± 5% or less, such as ± 2% or less, such as ± 1% or less, such as ± 0.5% or less, such as ± 0.2% or less, such as ± 0.1% or less, such as ± It can refer to 0.05% or less.

  Bulk solidified amorphous alloys, or bulk metallic glass (“BMG”), is a recently developed class of metallic materials. These alloys can be solidified and cooled at a relatively moderate rate, and they maintain an amorphous, amorphous (ie, vitreous) state at room temperature. Amorphous alloys have many superior properties than their crystalline counterparts. However, if the cooling rate is not sufficiently high, crystals may form within the alloy during cooling, and so the benefits of the amorphous state may be lost. For example, one important challenge associated with the manufacture of bulk amorphous alloy parts is the partial crystallization of those parts, either by slow cooling or by impurities in the alloy raw material. Within BMG parts, a high degree of amorphization (and conversely, a low degree of crystallinity) is desirable, so there is a need to develop a method for casting BMG parts with a controlled amount of amorphization. There is.

  FIG. 1 (obtained from US Pat. No. 7,575,040) is an exemplary bulk solidified amorphous alloy from the VIT-001 series of Zr—Ti—Ni—Cu—Be type manufactured by Liquidmetal Technology. The viscosity-temperature graph of is shown. It should be noted that there is no clear liquid / solid transformation for bulk solidifying amorphous metals during the formation of amorphous solids. This molten alloy becomes increasingly viscous with increasing supercooling until it approaches a solid form near the glass transition temperature. Thus, the temperature of the solidification front for the bulk solidified amorphous alloy can be near the glass transition temperature, at which point the alloy effectively acts as a solid for the purpose of drawing the quenched amorphous sheet product.

  FIG. 2 (obtained from US Pat. No. 7,575,040) shows a time-temperature-transformation (TTT) cooling curve, or TTT diagram, of an exemplary bulk solidified amorphous alloy. Bulk solidified amorphous metals, like conventional metals, do not undergo liquid / solid crystallization transformations upon cooling. Instead, highly fluid, amorphous forms of metals found at high temperatures (near the “melting temperature” Tm) become more viscous as the temperature is reduced (to near the glass transition temperature Tg). Finally, it exhibits the external physical properties of conventional solids.

  For bulk solidified amorphous metals, the “melting temperature” Tm can be defined as the thermodynamic liquid phase temperature of the corresponding crystal phase, even though there is no liquid / crystallization transformation. Under this regime, the viscosity at the melting temperature of the bulk solidified amorphous alloy can range from about 0.1 poise to about 10,000 poise, and in some cases, less than 0.01 poise. . This lower viscosity at the “melting temperature” results in faster and complete filling of complex parts of the shell / mold with bulk solidified amorphous metal to form BMG parts. In addition, the cooling rate of the molten metal to form the BMG part is such that the time-temperature profile during cooling does not cross the nose shaped region that bounds the crystallization region in the TTT diagram of FIG. There must be. In FIG. 2, T nose is the critical crystallization temperature Tx where crystallization is most rapid and occurs on the shortest time scale.

The supercooled liquid region, i.e., the temperature region from Tg to Tx, demonstrates extreme stability against crystallization of the bulk solidified alloy. Within this temperature range, the bulk solidified alloy can exist as a highly viscous liquid. The viscosity of the bulk solidified alloy in this supercooled liquid region ranges from 10 ¹² Pa · s at the glass transition temperature to 105 Pa · s at the high temperature limit of the supercooled liquid region, which is the crystallization temperature. Can change. A liquid having such a viscosity can experience substantial plastic strain under pressure. Embodiments herein utilize the large plastic formability within this supercooled liquid region as a forming and separating method.

  It is necessary to clarify Tx. Technically, the nose shaped curve shown in the TTT diagram describes Tx as a function of temperature and time. Therefore, Tx is reached when it hits this TTT curve, regardless of the trajectory followed during heating or cooling of the metal alloy. In FIG. 2, Tx is shown as a dashed line because Tx can vary from proximal Tm to proximal Tg.

  The schematic TTT diagram of FIG. 2 shows a die casting processing method in which the time-temperature trajectory (shown as (1) as an exemplary trajectory) does not hit the TTT curve and is greater than or equal to Tm and less than Tg. During die casting, this forming is performed at the same time as the rapid cooling to avoid the trajectory hitting the TTT curve. Time-temperature trajectory (shown as exemplary trajectories (2), (3), and (4)) does not hit the TTT curve, and processing related to superplastic forming (SPF) from below Tg to below Tm Processing method. In SPF, amorphous BMG is reheated into the supercooled liquid region and the available processing window can be much larger than die casting, resulting in better process controllability. The SPF process does not require rapid cooling to avoid crystallization during cooling. Also, as shown by exemplary trajectories (2), (3), and (4), SPF is performed with the highest temperature during SPF being above or below T nose and up to about Tm can do. Although the temperature of one amorphous alloy is raised, when it is managed so as to avoid hitting the TTT curve, Tx is not reached even when heated to “Tg to Tm”.

The typical differential scanning calorimeter (DSC) heating curve of bulk solidified amorphous alloys, obtained at a heating rate of 20 ° C./min, largely describes the specific trajectory across the TTT data. There will be a Tg at temperature, a Tx where the DSC heating ramp intersects the onset of TTT crystallization, and finally a melting peak where the same trajectory intersects the temperature range for melting. Avoid TTT curves completely when heating bulk solidified amorphous alloys at a rapid heating rate as shown by the up-tilted portions of trajectories (2), (3), and (4) in FIG. And DSC data show a glass transition upon heating but no Tx. Another way of thinking about this is that the trajectories (2), (3), and (4) are within the TTT curve nose (and further above) to the temperature of the Tg line, as long as they do not hit the crystallization curve. It can fit in any place. That simply means that as the processing temperature increases, the horizontal flats in the trajectory can become much shorter.
phase

  As used herein, the term “phase” can refer to what can be found in a thermodynamic phase diagram. A phase is a region of space (eg, a thermodynamic system) throughout which all physical properties of the material are essentially uniform. Examples of physical properties include density, refractive index, chemical composition, and lattice periodicity. A simple description of a phase is a region of material that is chemically uniform, physically distinct, and / or mechanically separable. For example, in a system consisting of ice and water in a glass jar, the ice cube is one phase, water is the second phase, and humid air above the water is the third phase. Jar glass is another separate phase. A phase can refer to a solid solution and can be a compound such as a two-component, three-component, four-component or higher solution or intermetallic compound. As another example, the amorphous phase is completely different from the crystalline phase. Metals, transition metals, and non-metals

  The term “metal” refers to an electropositive chemical element. As used herein, the term “element” generally refers to an element that can be found in the periodic table. Physically, ground state metal atoms contain a partially filled energy band that makes the empty state close to the occupied state. The term “transition metal” is the third in the periodic table that has an incomplete internal electron shell and serves as a transition link between the most electropositive and the least electropositive in a set of elements. It is one of the metal elements within the range of Group 12 to Group 12. Transition metals are characterized by multiple valences, colored compounds, and the ability to form stable complex ions. The term “nonmetal” refers to a chemical element that does not have the ability to lose electrons and form a cation.

  Depending on the application, any suitable non-metallic elements, or combinations thereof, can be used. An alloy (or “alloy composition”) may include a plurality of non-metallic elements, such as at least two, at least three, at least four or more non-metallic elements. The nonmetallic element can be any element found within Groups 13-17 in the periodic table. For example, the nonmetallic elements are F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge, Sn, Pb, and B. It can be any one of them. In some cases, the non-metallic element can also refer to a specific metalloid within Group 13 to Group 17 (eg, B, Si, Ge, As, Sb, Te, and Po). In one embodiment, the non-metallic element can include B, Si, C, P, or a combination thereof. Thus, for example, the alloy can include borides or carbides, or both.

  Transition metal elements are scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten , Rhenium, osmium, iridium, platinum, gold, mercury, rutherfordium, dobnium, seaborgium, bolium, hassium, mitonium, ununnilium, ununnium, and ununbium. In one embodiment, the transition metal element-containing BMG is Sc, Y, La, Ac, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, It may have at least one of Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. Depending on the application, any suitable transition metal element, or combinations thereof, can be used. The alloy composition may include a plurality of transition metal elements, such as at least 2, at least 3, at least 4 or more transition metal elements.

  An alloy or alloy “sample” or “specimen” alloy described herein may have any shape or size. For example, the alloy can have a particulate shape, which can have a shape such as a sphere, ellipse, wire, rod, sheet, flake, or irregular shape. The microparticles can have any size. For example, the microparticles can be about 5 micrometers to about 80 micrometers, such as about 10 micrometers to about 60 micrometers, such as about 15 micrometers to about 50 micrometers, such as about 15 micrometers to about 45 micrometers, etc. It may have an average diameter of about 1 micrometer to about 100 micrometers, such as about 25 micrometers to about 35 micrometers, such as about 20 micrometers to about 40 micrometers. For example, in one embodiment, the average diameter of the microparticles is from about 25 micrometers to about 44 micrometers. In some embodiments, smaller particles, such as those in the nanometer range, or larger particles, such as those larger than 100 micrometers, can be used.

The alloy sample or specimen can also be of much larger dimensions. For example, it can be a bulk structural component such as an ingot, an electronics enclosure / casing, or even part of a structural component having dimensions in the millimeter, centimeter, or meter range.
Solid solution

The term “solid solution” refers to the solid form of the solution. The term “solution” refers to a mixture of two or more substances that can be a solid, liquid, gas, or a combination thereof. This mixture can be homogeneous or heterogeneous. The term “mixture” is a composition of two or more substances that can be combined with each other and generally separated. In general, the two or more substances are not combined with each other.
alloy

  In some embodiments, the alloy compositions described herein can be fully alloyed. In one embodiment, an “alloy” refers to a homogenous mixture or solid solution of two or more metals in which one atom replaces another atom or occupies an interstitial position between atoms. For example, brass is an alloy of zinc and copper. An alloy can refer to a partial or complete solid solution of one or more elements in a metal matrix, such as one or more compounds in the metal matrix, as opposed to a composite material. The term alloy herein may refer to both a fully solid solution alloy that may exhibit a single solid phase microstructure and a partial solution that may exhibit two or more phases. The alloy compositions described herein can refer to those comprising an alloy or those comprising an alloy-containing composite material.

Thus, a fully alloyed alloy can have a homogeneous distribution of its constituents, whether in solid solution phase, compound phase, or both. As used herein, the term “fully alloyed” can describe slight variations within tolerances. For example, the term includes at least 90% alloying, such as at least 95% alloying, such as at least 99% alloying, such as at least 99.5% alloying, such as at least 99.9% alloying. Can point. Percentages herein can refer to either volume percentages or weight percentages, depending on the context. These percentages can be balanced by impurities, which can be in terms of compositions or phases that are not part of the alloy.
Amorphous or amorphous solid

  An “amorphous” or “amorphous solid” is a solid that lacks the lattice periodicity characteristic of crystals. As used herein, “amorphous solid” includes “glass”, which is an amorphous solid that softens and transforms into a liquid state upon heating through the glass transition. In general, amorphous materials lack the long-range order characteristic of crystals, but these amorphous materials can possess some short-range order on the atomic length scale due to the nature of chemical bonds. A distinction between amorphous and crystalline solids can be made based on lattice periodicity determined by structural characterization techniques such as X-ray diffraction and transmission electron microscopy.

  The terms “order” and “disorder” indicate the presence or absence of any symmetry or correlation within a multiparticulate system. The terms “long-range order” and “short-range order” distinguish order within a material based on a length scale.

  The most rigorous form of order in a solid is lattice periodicity, and a specific pattern (atom arrangement in a unit cell) is repeated many times to form a translational uniform space filling of the space. This lattice periodicity is a defining characteristic of crystals. The possible symmetries are grouped into 14 Bravey lattices and 230 space groups.

  Lattice periodicity suggests long-range order. If only one unit cell is known, its translational symmetry makes it possible to accurately predict all atomic arrangements at an arbitrary distance. The converse is generally true, except in the case of, for example, quasicrystals that have a completely deterministic filling but do not possess lattice periodicity.

  Long-range order characterizes a physical system in which remote parts of the same sample exhibit correlated behavior. This long-range order can be expressed as a correlation function, that is, the next spin-spin correlation function. G (x, x ') = <s (x), s (x')>

  In the above function, s is a spin quantum number and x is a distance function in a specific system. This function is equal to the identity element when x = x ′ and decreases as the distance | x−x ′ | Typically, this function decays exponentially to zero over long distances and the system is considered disordered. However, if this correlation function decays to a constant value with a large | x−x ′ |, it can be stated that the system possesses long-range order. If this function decays to zero as a power of distance, it can be called quasi-long-range order. Note that what constitutes a large value of | x-x '| is relative.

  A system can be extended by presenting a quenching disorder, eg, spin glass, if some of the parameters that define its behavior are random variables that do not evolve over time (ie, they are quenched or frozen). it can. This quenching disorder is the opposite of the annealing disorder in which the random variable itself can develop. Embodiments herein include systems that include a quenching disorder.

  The alloys described herein can be crystalline, partially crystalline, amorphous, or substantially amorphous. For example, an alloy sample / specimen may include at least some degree of crystallinity, with the grains / crystals having a size in the nanometer and / or micrometer range. Alternatively, the alloy can be substantially amorphous, such as sufficiently amorphous. In one embodiment, the alloy composition is not at least substantially amorphous, such as substantially crystalline, such as fully crystalline.

In one embodiment, the presence of one or more crystals in another amorphous alloy can be interpreted as a “crystalline phase” in that alloy. The degree of crystallinity of an alloy (or in some embodiments, “crystallinity” for short) can refer to the amount of crystalline phase present in the alloy. The degree can refer, for example, to the fraction of crystals present in the alloy. This fraction can refer to a volume fraction or a weight fraction, depending on the context. A measure of how “amorphous” an amorphous alloy can be is the degree of amorphization. The degree of amorphization can be measured from the viewpoint of the degree of crystallinity. For example, in one embodiment, an alloy having a low degree of crystallinity can be described as having a high degree of amorphousness. In one embodiment, for example, an alloy having 60% by volume crystalline phase may have 40% by volume amorphous phase.
Amorphous alloy or amorphous metal

  “Amorphous alloy” means an amorphous content greater than 50% by volume, preferably greater than 90% by volume, more preferably greater than 95% by volume, most preferably greater than 99% by volume to almost 100% by volume. % Is an alloy with an amorphous content. As noted above, it should be noted that alloys with a high degree of amorphization have an equally low degree of crystallinity. An “amorphous metal” is an amorphous metal material having a disordered atomic scale structure. By being crystalline, amorphous alloys are amorphous, as opposed to most metals, which have a highly ordered atomic arrangement. The material in which such a disordered structure is created directly from the liquid state during cooling may be referred to as “glass”. Thus, amorphous metals are commonly referred to as “metallic glass” or “glass metal”. In one embodiment, bulk metallic glass (“BMG”) can refer to an alloy whose microstructure is at least partially amorphous. However, in addition to extreme rapid cooling, there are several ways to create amorphous metals, including physical vapor deposition, solid phase reaction, ion irradiation, melt spinning, and mechanical alloying. Amorphous alloys can be a single class of materials regardless of how they are prepared.

  Amorphous metal can be produced through various quenching methods. For example, amorphous metal can be created by sputtering molten metal onto a rotating metal disk. A quench of about several million degrees per second can be too fast for crystals to form, so that the metal is “fixed” in the glassy state. Amorphous metals / alloys can also be created with critical cooling rates that are slow enough to allow the formation of thick layer amorphous structures, such as bulk metallic glass.

  The terms “bulk metallic glass” (“BMG”), bulk amorphous alloy (“BAA”), and bulk solidified amorphous alloy are used interchangeably herein. These terms refer to an amorphous alloy having a minimum dimension in the range of at least millimeters. For example, the dimension is at least about 0, such as at least about 1 mm, at least about 2 mm, at least about 4 mm, at least about 5 mm, at least about 6 mm, at least about 8 mm, at least about 10 mm, at least about 12 mm, etc. .5 mm. Depending on the geometry, the dimensions can refer to diameter, radius, thickness, width, length, etc. The BMG may also be a metallic glass having at least one dimension in the centimeter range, such as at least about 1.0 cm, such as at least about 2.0 cm, such as at least about 5.0 cm, such as at least about 10.0 cm. You can also. In some embodiments, the BMG may have at least one dimension in the range of at least meters. BMG can exhibit any of the shapes or forms described above with respect to metallic glass. Accordingly, the BMG described herein may differ from thin films made by conventional deposition techniques in one important aspect in some embodiments, the former BMG being the latter The size can be much larger than that of the thin film.

  The amorphous metal can be an alloy rather than a pure metal. This alloy can contain atoms of significantly different sizes, resulting in a low free volume in the molten state (and therefore has a viscosity that is orders of magnitude higher than other metals and alloys). . This viscosity prevents atoms from moving sufficiently to form an ordered lattice. This material structure can provide low shrinkage during cooling and resistance to plastic deformation. This absence of grain boundaries, which in some cases is a weakness of crystalline materials, can result in better resistance to wear and corrosion, for example. In one embodiment, although technically glass, amorphous metals can also be much stronger and less brittle than oxide glasses and ceramics.

  The thermal conductivity of amorphous materials can be lower than the thermal conductivity of their crystalline counterparts. In order to achieve the formation of an amorphous structure even during slower cooling, an alloy is made with three or more components, resulting in a composite crystal unit with higher potential energy and lower probability of formation. be able to. The formation of an amorphous alloy depends on several factors: the composition of the alloy components and the atomic radii of the components (preferably greater than 12% in order to achieve high packing density and low free volume). And the negative heat of mixing of the combination of components that prevents crystal nucleation and extends the time that the molten metal remains supercooled. However, since the formation of amorphous alloys is based on a wide variety of variables, it may be difficult to determine in advance whether the alloy composition forms an amorphous alloy.

  For example, amorphous alloys of boron, silicon, phosphorus, and other glass formers with magnetic metals (iron, cobalt, nickel) can be magnetic with low coercivity and high electrical resistance. This high resistance results in low loss due to eddy currents when exposed to an alternating magnetic field, which is a characteristic useful as a magnetic core for a transformer, for example.

  Amorphous alloys can have a variety of properties that are potentially useful. Specifically, amorphous alloys tend to be stronger than crystalline alloys of similar chemical composition, and they can withstand greater reversible (“elastic”) deformation than crystalline alloys. Amorphous metals derive their strength directly from their amorphous structure, which can have no defects (such as dislocations) that limit the strength of the crystalline alloy. For example, one state-of-the-art amorphous metal, known as Vitreloy ™, has a tensile strength approximately twice that of high-grade titanium. In some embodiments, the metallic glass at room temperature is not ductile and breaks suddenly when tension is applied, which is not evident in imminent failure, so in applications where reliability is important, Limit applicability of the material. Therefore, to overcome this challenge, metal matrix composites with a metallic glass matrix containing ductile crystalline metal dendritic particles or fibers can be used. Alternatively, BMG with less elements (eg, Ni) that tend to cause seriousness can be used. For example, by using BMG that does not contain Ni, the ductility of the BMG can be improved.

  Another useful property of bulk amorphous alloys is that they are intrinsic glasses, in other words they can soften and flow with heating. This allows easy processing, such as by injection molding, in much the same way as a polymer. As a result, amorphous alloys can be used to make sports equipment, medical devices, electronic components and equipment, and thin films. Amorphous metal thin films can be deposited as protective coatings via high speed oxygen fuel technology.

  The material can have an amorphous phase, a crystalline phase, or both. These amorphous and crystalline phases can have the same chemical composition and differ only in microstructure (ie, one is amorphous and the other is crystalline). Microstructure in one embodiment refers to the structure of the material as revealed by a microscope with a magnification of 25 × or greater. Alternatively, these two phases can have different chemical compositions and microstructures. For example, the composition can be partially amorphous, substantially amorphous, or fully amorphous.

  As described above, the degree of amorphization (and conversely, the degree of crystallinity) can be measured by the fraction of crystals present in the alloy. The degree can refer to the volume fraction or weight fraction of the crystalline phase present in the alloy. A partially amorphous composition includes at least about 10%, such as at least about 20%, such as at least about 40%, such as at least about 60%, such as at least about 80%, such as at least about 90%. , Which can refer to a composition at least about 5% by volume of which is in an amorphous phase. The terms “substantially” and “about” are defined elsewhere in this specification. Thus, a composition that is at least substantially amorphous includes at least about 99.8 vol%, such as at least about 95 vol%, such as at least about 98 vol%, such as at least about 99 vol%, such as at least about 99.5 vol%. %, Such as at least about 99.9% by volume, at least about 90% by volume of which is amorphous. In one embodiment, the substantially amorphous composition can have any attendant minor crystalline phase present therein.

  In one embodiment, the amorphous alloy composition can be homogeneous with respect to the amorphous phase. A substance with a uniform composition is homogeneous. This is in contrast to materials that are heterogeneous. The term “composition” refers to the chemical composition and / or microstructure in a substance. A substance is homogeneous when the volume of the substance is divided in half and both halves have substantially the same composition. For example, a particulate suspension is homogeneous when the volume of the particulate suspension is divided in half and both halves have substantially the same volume of particles. However, it may be possible to see individual particles under a microscope. Another example of a homogeneous material is air, where the various components in the air are equally floating, but the particles, gases, and liquids in the air can be analyzed separately or separated from the air. You can also.

  A composition that is homogeneous with respect to an amorphous alloy can refer to one having an amorphous phase that is distributed substantially uniformly throughout its microstructure. In other words, the composition macroscopically comprises an amorphous alloy that is distributed substantially uniformly throughout the composition. In an alternative embodiment, the composition can be of a composite material having an amorphous phase with a non-amorphous phase therein. This non-amorphous phase can be a single crystal or multiple crystals. The crystals can be in the form of particulates of any shape, such as spherical, oval, wire, rod, sheet, flake, or irregular shape. In one embodiment, the crystals can have a dendritic morphology. For example, an at least partially amorphous composite composition may have a crystalline phase in the form of dendrites dispersed in an amorphous phase matrix, and this dispersion may be uniform or non-uniform. In one embodiment, the amorphous phase and the crystalline phase can have the same chemical composition or different chemical compositions, and the phases can have substantially the same chemical composition. In another embodiment, the crystalline phase can be more ductile than the BMG phase.

  The methods described herein may be applicable to any type of amorphous alloy. Similarly, the amorphous alloy described herein as a component of the composition or article can be of any type. The amorphous alloy may include elements of Zr, Hf, Ti, Cu, Ni, Pt, Pd, Fe, Mg, Au, La, Ag, Al, Mo, Nb, Be, or combinations thereof. That is, the alloy may include any combination of these elements in its chemical formula or chemical composition. These elements can be present in various weight or volume percentages. For example, an iron “base” alloy can refer to an alloy having a non-negligible weight percentage of iron present therein, the weight percentage being at least about 40% by weight, for example, at least about 40% by weight. It may be at least about 20%, such as 50%, such as at least about 60%, such as at least about 80%. Alternatively, in one embodiment, the percentages described above can be volume percentages instead of weight percentages. Thus, the amorphous alloy can be a zirconium base, a titanium base, a platinum base, a palladium base, a gold base, a silver base, a copper base, an iron base, a nickel base, an aluminum base, a molybdenum base, and the like. The alloy may also not include any of the above-described elements to suit a particular purpose. For example, in some embodiments, the alloy, or a composition comprising the alloy, can be substantially free of nickel, aluminum, titanium, beryllium, or combinations thereof. In one embodiment, the alloy or composite material does not include any nickel, aluminum, titanium, beryllium, or combinations thereof.

For example, the amorphous alloy can have the formula (Zr, Ti) _a (Ni, Cu, Fe) _b (Be, Al, Si, B) _c , where a, b, and c are Each represents a weight percentage or an atomic percentage. In one embodiment, in atomic percent, a is in the range of 30-75, b is in the range of 5-60, and c is in the range of 0-50. Alternatively, the amorphous alloy can have the formula (Zr, Ti) _a (Ni, Cu) _b (Be) _c , where a, b, and c are weight percentages or atomic percentages, respectively. Represent. In one embodiment, in atomic percent, a is in the range of 40-75, b is in the range of 5-50, and c is in the range of 5-50. The alloy may also have the formula (Zr, Ti) _a (Ni, Cu) _b (Be) _c , where a, b, and c represent weight percentage or atomic percentage, respectively. In one embodiment, in atomic percent, a is in the range of 45-65, b is in the range of 7.5-35, and c is in the range of 10-37.5. Alternatively, the alloy can have the formula (Zr) _a (Nb, Ti) _b (Ni, Cu) _c (Al) _d , where a, b, c, and d are each a weight percentage. Or it represents atomic percentage. In one embodiment, in atomic percent, a is in the range of 45-65, b is in the range of 0-10, c is in the range of 20-40, and d is in the range of 7.5-15. . One exemplary embodiment of the above alloy system is Zr-Ti-Ni- of the trade name Vitreloy (TM), such as Vitreloy-1 and Vitreloy-101, as manufactured by Liquidmetal Technologies (CA, USA). It is a Cu-Be based amorphous alloy. Some examples of various systems of amorphous alloys are listed in Tables 1 and 2.

  Other exemplary iron-based alloys include the compositions disclosed in, for example, US Patent Application Publication Nos. 2007/0079907 and 2008/0118387. These compositions include the Fe (Mn, Co, Ni, Cu) (C, Si, B, P, Al) system, Fe content is 60-75 atomic percent, (Mn, Co, Ni, The sum of Cu) is in the range of 5-25 atomic percent and the sum of (C, Si, B, P, Al) is in the range of 8-20 atomic percent, with an exemplary composition being Fe48Cr15Mo14Y2C15B6. Fe-Cr-Mo- (Y, Ln) -CB, Co-Cr-Mo-Ln-CB, Fe-Mn-Cr-Mo- (Y, Ln) -CB, (Fe , Cr, Co)-(Mo, Mn)-(C, B) -Y, Fe- (Co, Ni)-(Zr, Nb, Ta)-(Mo, W) -B, Fe- (Al, Ga) )-(P, C, B, Si, Ge), Fe- (Co, Cr, Mo, Ga, Sb) -P-B-C, (Fe, Co) -B-Si-Nb alloy, and Fe- An alloy system described by (Cr-Mo)-(C, B) -Tm is mentioned, Ln is a lanthanide element, and Tm is a transition metal element. In addition, this amorphous alloy can be obtained from the exemplary compositions Fe80P12.5C5B2.5, Fe80PllC5B2.5Sil. 5, Fe74.5Mo5.5P12.5C5B2.5, Fe74.5Mo5.5PllC5B2.5Sil. 5, Fe70Mo5Ni5P12.5C5B2.5, Fe70Mo5Ni5PllC5B2.5Sil. 5, Fe68Mo5Ni5Cr2P12.5C5B2.5, and Fe68Mo5Ni5Cr2PllC5B2.5Sil. It can be one of five.

These amorphous alloys can also be iron alloys, such as (Fe, Ni, Co) based alloys. Examples of such compositions are US Pat. Nos. 6,325,868, 5,288,344, 5,368,659, 5,618,359, and 5,735. , 975, Inoue et al., Appl. Phys. Lett. , Volume 71, p 464 (1997), Shen et al., Mater. Trans. , JIM, Volume 42, p 2136 (2001), and Japanese Patent Application No. 200126277 (Publication No. 2001303218 (A)). One exemplary composition is Fe ₇₂ Al ₅ Ga ₂ P ₁₁ C ₆ B ₄ . Another example is Fe ₇₂ Al ₇ Zr ₁₀ Mo ₅ W ₂ B ₁₅ . Another iron-based alloy system that can be used for coating herein is disclosed in U.S. Patent Application Publication No. 2010/0084052, the amorphous metal having a composition described in parentheses, for example. Of manganese (1 to 3 atomic%), yttrium (0.1 to 10 atomic%), and silicon (0.3 to 3.1 atomic%), and the composition described in parentheses The following elements in the specified range: Chromium (15-20 atom%), Molybdenum (2-15 atom%) Tungsten (1-3 atom%), Boron (5-16 atom%), Carbon (3-16 atom%) And the balance iron.

  The amorphous alloy system described above may further include additional elements, such as additional transition metal elements including Nb, Cr, V, and Co. These additive elements may be present at about 30 wt% or less, such as about 20 wt% or less, such as about 10 wt% or less, such as about 5 wt%. In one embodiment, the optional additive element is at least one of cobalt, manganese, zirconium, tantalum, niobium, tungsten, yttrium, titanium, vanadium, and hafnium, forming carbides and wear resistant. Further improve the properties and corrosion resistance. Further optional elements may include phosphorus, germanium, and arsenic, up to a total of about 2%, preferably less than 1%, to lower the melting point. Other minor impurities should be less than about 2%, preferably less than 0.5%.

  In some embodiments, a composition having an amorphous alloy can include a small amount of impurities. By intentionally adding impurity elements, the properties of the composition, such as improved mechanical properties (eg, hardness, strength, fracture mechanism, etc.) and / or improved corrosion resistance can be modified. Alternatively, the impurities may be present as inevitable incidental impurities, such as those obtained as processing and manufacturing by-products. The impurities may be about 10 wt% or less, such as about 5 wt% or less, such as about 2 wt% or less, such as about 1 wt% or less, such as about 0.5 wt% or less, such as about 0.1 wt% or less. be able to. In some embodiments, these percentages can be volume percentages instead of weight percentages. In one embodiment, the alloy sample / composition consists essentially of an amorphous alloy (having only a small amount of incidental impurities). In another embodiment, the composition comprises an amorphous alloy (having no observable trace impurities).

  In one embodiment, the final part exceeded the critical cast thickness of the bulk solidified amorphous alloy.

  In embodiments herein, superplastic forming is enabled by the presence of a supercooled liquid region in which the bulk solidified amorphous alloy can exist as a high viscosity liquid. Large plastic deformation can be obtained. The ability to plastically deform significantly in the supercooled liquid region is used for the molding and / or cutting process. In contrast to solids, this liquid bulk solidified alloy deforms locally, which greatly reduces the energy required for cutting and forming. The ease of cutting and forming varies with the temperature of the alloy, mold and cutting tool. As the temperature increases, the viscosity decreases, resulting in easier cutting and molding.

  Embodiments herein can utilize a thermoplastic molding process using an amorphous alloy, for example, performed at Tg-Tx. As used herein, Tx and Tg are determined from standard DSC measurements at typical heating rates (eg, 20 ° C./min) as the temperature of onset of crystallization and the temperature of onset of glass transition. .

The amorphous alloy component can have a critical casting thickness, and the final part can have a thickness greater than its critical casting thickness. Furthermore, the time and temperature of the heating and shaping operations are selected such that the elastic strain limit of the amorphous alloy can be substantially maintained at 1.0% or higher, preferably 1.5% or higher. In the context of embodiments herein, the temperature near the glass transition means that the molding temperature can be less than the glass transition, near the glass transition temperature or glass transition temperature, and above the glass transition temperature, it is preferably a temperature lower than the crystallization temperature T _x. The cooling step is performed at a rate similar to the heating rate in the heating step, preferably at a rate exceeding the heating rate in the heating step. The cooling step is also preferably accomplished while the forming and shaping loads are still maintained.
Electronic devices

  Embodiments herein may be useful in the fabrication of electronic devices that use BMG. As used herein, an electronic device can refer to any electronic device known in the art. For example, the electronic device can be any communication device such as a phone such as a mobile phone and a landline phone, or a smartphone including, for example, iPhone ™, and an e-mail sending / receiving device. The electronic device can be part of a display, such as a digital display, TV monitor, electronic book reader, portable web browser (eg, iPad ™), and computer monitor. The electronic device can also be an entertainment device including a music player such as a portable DVD player, a conventional DVD player, a Blu-ray disc player, a video game console, a portable music player (eg, iPod ™), and the like. . The electronic device can also be part of a device that provides control (eg, Apple TV ™), such as controlling image, video, audio streaming, or remote control for an electronic device. It can be a device. This electronic device can be part of a computer or a computer accessory such as a hard drive tower enclosure or casing, laptop enclosure, laptop keyboard, laptop trackpad, desktop keyboard, mouse, and speakers. . This article can also be applied to devices such as watches or watches.

  The raw material containing BMG can be a starting material for injection molding. For example, the raw material can be melted and immediately injected into a mold. The molten raw material in the mold can be cooled at a rate sufficient to form a part that is completely amorphous. Alternatively, the melted raw material in the mold is at a rate to form a part that is completely crystalline (greater than 99% by weight crystalline material) or partly crystalline and partly amorphous. Can be cooled at a rate to form The raw material is preferably melted by induction heating.

  In one embodiment shown in FIG. 3, the powder is consolidated to form the raw material. This powder contains the elements of BMG, and the elements of the powder have the same weight percentage as that of BMG. This powder may comprise BMG in powder form. The powder may comprise a composite or alloy of BMG elements. This powder can be consolidated with a binder. The binder is a material that evaporates at the melting temperature of the powder, one of the elements of BMG (eg, if BMG contains Sn, Sn powder may function as a binder), a composite of multiple elements of BMG, or It can be an alloy of multiple elements of BMG. In one embodiment, the powder is consolidated into a sheath to form a raw material that does not melt at the melting temperature of the powder.

  In one embodiment, shown in FIG. 4, the powder is consolidated into a sheath to form a raw material that melts at the melting temperature of the powder. The powder and sheath as a whole consist of the elements of BMG, which elements have the same weight percentage as BMG. This powder may comprise BMG in powder form. The powder may comprise a composite or alloy of BMG elements. This powder can be consolidated with a binder. The binder is a material that evaporates at the melting temperature of the powder, one of the elements of BMG (eg, if BMG contains Sn, Sn powder can function as a binder), or a composite of multiple elements of BMG or Can be an alloy.

  In one embodiment, the composition of the powder can be adjusted to provide flexibility in the chemical composition of parts made from this raw material. For example, if the part requires a higher percentage of Ti, the powder can be adjusted by adding more components with more Ti. Such flexibility allows the formation of parts with various electrical, magnetic, temperature, or aesthetic properties, porosity. In one embodiment, the powder may include a material that does not melt with the powder during injection molding, so that the part can be a BMG composite with the material (eg, fibers, spheres) introduced.

  The powder can be consolidated by any suitable method such as hot pressing, cold pressing, extrusion, rapid discharge sintering and the like.

  The BMG raw material can be a starting material for injection molding. For example, the BMG raw material can be melted and injected into a mold. The molten BMG in the mold can be cooled at a rate that forms a part that is completely amorphous. Alternatively, the molten BMG raw material in this mold is at a rate to form a part that is completely crystalline (greater than 99% by weight crystalline material) or partially crystalline and partially amorphous. It can be cooled at the rate of forming the part. The BMG raw material is preferably melted by induction heating.

  Injection molding is a manufacturing process for creating parts from both thermoplastic and thermoset plastic materials. The material is fed into a heated barrel, mixed and pushed into the mold cavity where it cools and hardens into the shape of the mold cavity. The mold is typically made from a metal such as steel or aluminum and can be precision machined to form the desired part features. Injection molding is widely used to produce a variety of parts, from the smallest components of automobiles to body panels.

  A polymer is used for injection molding. Many polymers (sometimes called resins) can be used, including all thermoplastics, some thermosets, and some elastomers. In 1995, there were about 18,000 materials that could be used for injection molding, and the number increased by an average of 750 each year. Available materials are alloys or mixtures of materials that have been developed so far, which means that product designers can choose from a wide range of material options with exactly the right properties. The material is selected based on the strength and function required for the final part, but each material also has various parameters during molding that must be considered. Common polymers such as epoxies and phenolic resins are examples of thermosetting plastics, and nylon, polyethylene, and polystyrene are thermoplastics.

  The injection molding apparatus includes a material hopper, an injection ram or screw type plunger, and a heating device. These are also known as presses and hold a mold in which the components are molded. The press is rated by tonnage, which represents the amount of clamping force that the device can apply. This force keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with higher numbers being used in relatively few manufacturing operations. The total clamping force required is determined by the projected area of the part being molded. This projected area is multiplied by a clamping force of 2 to 8 tons per square inch of the projected area. As a rule of thumb, 4 or 5 tons per square inch can be used for most products. If the plastic material is very hard, a higher injection pressure is required to fill the mold, and therefore a larger clamping tonnage is required to close and hold the mold. Is done. The required force can also be determined by the material being used and the size of the part, with larger parts requiring higher clamping forces.

  This mold includes two main components, an injection mold (A plate) and a protruding mold (B plate). The raw material enters the mold from the “muzzle” of the injection mold. The sprue bush is used to tightly seal against the nozzle of the injection barrel of the molding apparatus and to allow the molten material to flow from the barrel to the mold (also referred to as a mold cavity). The sprue bushing guides the melted raw material through the channel to the mold cavity image, which is machined into the faces of the A and B plates. This channel is also called a “runner” because the raw material runs along. The molten material flows through the runner, enters one or more dedicated gates, and flows into the mold cavity shape to form the desired part.

  The mold can be cooled by passing a coolant (usually water) through a series of holes drilled through the mold plate and connected by a hose to form a continuous path. it can. This coolant absorbs heat from the mold (which absorbs heat from the hot plastic) and maintains the mold at the proper temperature to cure the plastic at the most efficient rate .

  Some molds allow the pre-molded part to be reinserted, which makes it possible to form a new plastic layer around the first part. This is often referred to as overmolding. A two-shot or multi-shot mold is designed to “overmold” within a single molding cycle, which is a process on a dedicated injection molding machine with two or more injection units. Must be processed. This process is actually an injection molding process performed twice. In the first step, the base color material is molded into a basic shape, which includes a space for the second shot. A second material of a different color is then injection molded into those spaces. For example, the push buttons and keys made by this process have a sign that is not likely to wear out over time and remains legible.

  The sequence of events during part injection molding is called the injection molding cycle. This cycle begins when the mold closes, followed by the injection of the raw material into the mold cavity. After the mold cavity is filled, any material shrinkage is compensated by maintaining the holding pressure. In the next step, the screw turns and the next shot is fed to the front screw. Thereby, the screw is pulled back when the next shot is prepared. After the part is sufficiently cooled, the mold is opened and the part is discharged.

Claims (17)

A method for producing a raw material containing bulk metallic glass (BMG),
The method includes the step of compacting the powder;
The method wherein the powder comprises an element of the BMG, the element of the BMG in the powder has substantially the same weight percentage as that of the BMG, and the powder is consolidated with a binder.   The method of claim 1, wherein the powder comprises the BMG in powder form.   The method of claim 1, wherein the powder comprises a complex of a plurality of the elements of the BMG.   The method of claim 1, wherein the powder comprises an alloy of a plurality of the elements of the BMG.   The method of claim 1, wherein the binder is a material that evaporates at the melting temperature of the powder.   The method of claim 1, wherein the binder is one of the element of the BMG, a complex of the elements of the BMG, and an alloy of the elements of the BMG.   The method of claim 1, wherein the powder is consolidated in a sheath and the sheath does not melt at the melting temperature of the powder. A method for producing a raw material containing BMG,
The method comprises the step of compacting the powder into a sheath;
The sheath melts at the melting temperature of the powder, the powder and the sheath both contain the BMG, and the elements of the BMG in the powder have substantially the same weight percent as that of the BMG; The method wherein the powder is consolidated with a binder.   The method of claim 8, wherein the powder comprises the BMG in powder form.   The method of claim 8, wherein the powder comprises a complex of a plurality of the elements of the BMG.   The method of claim 8, wherein the powder comprises an alloy of a plurality of the elements of the BMG.   The method of claim 1, wherein the binder is a material that evaporates at the melting temperature of the powder.   The method of claim 1, wherein the binder is one of the element of the BMG, a complex of the elements of the BMG, and an alloy of the elements of the BMG.   The method of claim 1, wherein the powder is consolidated by hot pressing, cold pressing, extrusion, or rapid discharge sintering.   The method of claim 8, wherein the powder is consolidated by hot pressing, cold pressing, extrusion, or rapid discharge sintering. A method for producing a part from a raw material containing BMG, the method comprising:
Determine the weight and composition of the powder based on the weight of the part and the desired composition so that the weight of each element of the desired composition of the part is essentially equal to the weight of the BMG element in the powder. And a process of
Compacting the powder to form the raw material;
Including
The method wherein the powder is consolidated with a binder. A method for producing a part from a raw material containing BMG, the method comprising:
The weight of the part and the desired composition, and the weight of the sheath, such that the weight of each element of the desired composition of the part is essentially equal to the total weight of the elements of BMG in the powder and in the sheath. And determining the weight and composition of the powder based on the composition;
Compacting the powder into the sheath to form the raw material;
Including
The method wherein the powder is consolidated with a binder.

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