Amorphous brazing foil

Last updated

An amorphous brazing foil (ABF) is a form of eutectic amorphous metal that serves as a filler metal in brazing operations. ABFs are composed of various transition metals (including nickel, iron, and copper) blended with metalloids like silicon, boron, and phosphorus. By precisely managing the concentration of these metalloids to achieve or approach the eutectic point, these alloys can undergo rapid solidification to form a ductile, amorphous foil. This process allows the ABF to effectively bond materials in the brazing process, providing a strong and seamless joint. [1]

Contents

Production

The production of an amorphous metal can be achieved by cooling the liquid alloy too rapidly to allow a crystal structure to form. Melt spinning, a traditional method, produces a 0.5–125 mm wide strip with a thickness of 20–50 µm. Cutting, stamping, etching, or other methods can transform the cooled metal into parts or preforms. [2]

Properties

A key characteristic of ABFs is their relatively low melting points, which typically range from 830 to 1200°C. This attribute is crucial for their application as filler metals in brazing. Due to their ductility and flexibility, ABFs present a viable alternative to filler metals in paste or powder form. This substitution offers notable advantages, such as the elimination of soot formation, a common drawback associated with residual organic solvents in paste-based fillers. Additionally, ABFs help minimize the formation of surface oxides, an issue frequently encountered with gas-atomized powder fillers, thereby enhancing the quality and integrity of the brazed joint. [1]

Usage

Amorphous brazing foils are used for brazing, a metallurgical process by which two pieces of metal are joined by melting and cooling a third "filler metal" between them. The use of preforms increases the capability of ABFs for use on an industrial scale, aiding machine assembly. [1]

Related Research Articles

<span class="mw-page-title-main">Solder</span> Alloy used to join metal pieces

Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable for use as solder should have a lower melting point than the pieces to be joined. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making electrical connections also needs to have favorable electrical characteristics.

<span class="mw-page-title-main">Cupronickel</span> Alloy of copper containing nickel

Cupronickel or copper–nickel (CuNi) is an alloy of copper with nickel, usually along with small quantities of other elements added for strength, such as iron and manganese. The copper content typically varies from 60 to 90 percent.

<span class="mw-page-title-main">Brazing</span> Metal-joining technique

Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.

<span class="mw-page-title-main">Amorphous metal</span> Solid metallic material with disordered atomic-scale structure

An amorphous metal is a solid metallic material, usually an alloy, with disordered atomic-scale structure. Most metals are crystalline in their solid state, which means they have a highly ordered arrangement of atoms. Amorphous metals are non-crystalline, and have a glass-like structure. But unlike common glasses, such as window glass, which are typically electrical insulators, amorphous metals have good electrical conductivity and can show metallic luster.

<span class="mw-page-title-main">Heating element</span> Device that converts electricity into heat

A heating element is a device used for conversion of electric energy into heat, consisting of a heating resistor and accessories. Heat is generated by the passage of electric current through a resistor through a process known as Joule Heating. Heating elements are used in household appliances, industrial equipment, and scientific instruments enabling them to perform tasks such as cooking, warming, or maintaining specific temperatures higher than the ambient.

Ferroalloy refers to various alloys of iron with a high proportion of one or more other elements such as manganese (Mn), aluminium (Al), or silicon (Si). They are used in the production of steels and alloys. The alloys impart distinctive qualities to steel and cast iron or serve important functions during production and are, therefore, closely associated with the iron and steel industry, the leading consumer of ferroalloys. The leading producers of ferroalloys in 2014 were China, South Africa, India, Russia and Kazakhstan, which accounted for 84% of the world production. World production of ferroalloys was estimated as 52.8 million tonnes in 2015.

<span class="mw-page-title-main">Superalloy</span> Alloy with higher durability than normal metals

A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Key characteristics of a superalloy include mechanical strength, thermal creep deformation resistance, surface stability, and corrosion and oxidation resistance.

In metalworking, a filler metal is a metal added in the making of a joint through welding, brazing, or soldering.

<span class="mw-page-title-main">Alloy steel</span> Steel alloyed with a variety of elements

Alloy steel is steel that is alloyed with a variety of elements in amounts between 1.0% and 50% by weight, typically to improve its mechanical properties.

Nickel aluminide refers to either of two widely used intermetallic compounds, Ni3Al or NiAl, but the term is sometimes used to refer to any nickel–aluminium alloy. These alloys are widely used because of their high strength even at high temperature, low density, corrosion resistance, and ease of production. Ni3Al is of specific interest as a precipitate in nickel-based superalloys, where it is called the γ' (gamma prime) phase. It gives these alloys high strength and creep resistance up to 0.7–0.8 of its melting temperature. Meanwhile, NiAl displays excellent properties such as lower density and higher melting temperature than those of Ni3Al, and good thermal conductivity and oxidation resistance. These properties make it attractive for special high-temperature applications like coatings on blades in gas turbines and jet engines. However, both these alloys have the disadvantage of being quite brittle at room temperature, with Ni3Al remaining brittle at high temperatures as well. To address this problem, has been shown that Ni3Al can be made ductile when manufactured in single-crystal form rather than in polycrystalline form.

Induction brazing is a process in which two or more materials are joined together by a filler metal that has a lower melting point than the base materials using induction heating. In induction heating, usually ferrous materials are heated rapidly from the electromagnetic field that is created by the alternating current from an induction coil.

<span class="mw-page-title-main">Soldering</span> Process of joining metal pieces with heated filler metal

Soldering is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint.

<span class="mw-page-title-main">Cobalt-chrome</span> Alloy of cobalt and chromium used in medical implants

Cobalt-chrome or cobalt-chromium (CoCr) is a metal alloy of cobalt and chromium. Cobalt-chrome has a very high specific strength and is commonly used in gas turbines, dental implants, and orthopedic implants.

<span class="mw-page-title-main">Materials for use in vacuum</span>

Materials for use in vacuum are materials that show very low rates of outgassing in vacuum and, where applicable, are tolerant to bake-out temperatures. The requirements grow increasingly stringent with the desired degree of vacuum to be achieved in the vacuum chamber. The materials can produce gas by several mechanisms. Molecules of gases and water can be adsorbed on the material surface. Materials may sublimate in vacuum. Or the gases can be released from porous materials or from cracks and crevices. Traces of lubricants, residues from machining, can be present on the surfaces. A specific risk is outgassing of solvents absorbed in plastics after cleaning.

Transient liquid phase diffusion bonding (TLPDB) is a joining process that has been applied for bonding many metallic and ceramic systems which cannot be bonded by conventional fusion welding techniques. The bonding process produces joints with a uniform composition profile, tolerant of surface oxides and geometrical defects. The bonding technique has been exploited in a wide range of applications, from the production and repair of turbine engines in the aerospace industry, to nuclear power plants, and in making connections to integrated circuit dies as a part of the microelectronics industry.

<span class="mw-page-title-main">Bismuth–indium</span>

The elements bismuth and indium have relatively low melting points when compared to other metals, and their alloy bismuth–indium (Bi–In) is classified as a fusible alloy. It has a melting point lower than the eutectic point of the tin–lead alloy. The most common application of the Bi-In alloy is as a low temperature solder, which can also contain, besides bismuth and indium, lead, cadmium, and tin.

Havar, or UNS R30004, is an alloy of cobalt, possessing a very high mechanical strength. It can be heat-treated. It is highly resistant to corrosion and is non-magnetic. It is biocompatible. It has high fatigue resistance. It is a precipitation hardening superalloy.

voestalpine Böhler Welding is a manufacturer of welding consumables, welding equipment and accessories with headquarters in Düsseldorf. The company owns over 50 subsidiaries in more than 25 countries, 2,300 employees, customers in approximately 150 countries and more than 1,000 distribution partners.

References

  1. 1 2 3 Rabinkin, A. (June 1, 2004). "Brazing with (NiCoCr)–B–Si amorphous brazing filler metals: Alloys, processing, joint structure, properties, applications". Science and Technology of Welding and Joining. 9 (3): 181–199. doi:10.1179/136217104225012300. ISSN   1362-1718. S2CID   136671451 via Taylor & Francis Online.
  2. Greer, A. Lindsay (1995-03-31). "Metallic Glasses". Science. 267 (5206): 1947–1953. Bibcode:1995Sci...267.1947G. doi:10.1126/science.267.5206.1947. ISSN   0036-8075. PMID   17770105. S2CID   12452422.