Typical Nonferrous Metals

  • To understand the importance of fundamental microstructural features and defects in the design and evolution of nonferrous alloys. The various alloys to be considered include copper base alloys, light metal alloys (titanium, aluminum and magnesium) and high temperature alloys (nickel and cobalt) .

  • To appreciate the use of these alloys in real world applications. In each class of alloys, different phase transformations and important phases formed from addition of different alloying elements will be discussed.

  • To understand the role of each alloying element in strengthening and stabilizing the phases via order-disorder or martensitic or other transformation.

  • To know the specific alloying elements that enhance corrosion resistance, high temperature oxidation resistance and creep resistance.

  • To know the factors that are used in the design and development of alloys for advanced applications.

  • To apply principles of alloy theory in the prediction of formation of different desirable or undesirable phases.

  • Aluminum: Aluminum is strong, lightweight, electrically- and thermally-conductive, and corrosion resistant. These properties can be enhanced through alloying. It is often anodized to help prevent corrosion. Its electrical conductivity make it an excellent choice for electrical applications such as wiring and conductors. Its strength-to-weight ratio makes it attractive in structural applications as well as cast aluminum engine components, e.g. blocks, heads, and manifolds. Its high reflectivity of infrared and visible radiation makes it desirable in headlights, light fixtures, and many insulation. It is also used as a paint pigment.

  • Copper: Copper is a natural occurring substance. The fact that it conducts heat and electricity means that it is used for wiring, tubing and pipe work. Copper has been used in various applications for centuries. It generally finds applications requiring high thermal and electrical conductivity. For example, the thermal conductivity of copper is almost ten times greater than ordinary steel. Therefore, it finds use as kitchen products, wiring and electrical applications, piping and tubing, and other such uses. Alloys of copper and zinc are termed brasses. Zinc is added to improve the strength and ductility of the alloy. There are many formulas for brasses which include other alloying elements than copper and zinc. Brass is used in decorative metal products, cartridge cases, piping and tubing, and many of the same application as copper.

  • Brass: A combination of copper and zinc, usually in the proportions of 65% to 35% respectively. Is used for ornamental purposes and within electrical fittings.

  • Bronze: Bronze is an alloy of copper and any other metal. As with brasses, there are many formulas for bronzes, depending on the application. Aluminum bronzes, tin bronzes, phosphor bronzes, nickel bronzes, and silicon bronzes are all examples of varying alloys. The principle alloying element determines the nomenclature. Bronzes are used in applications such as bearings, some limited structural applications, decorative uses, and applications which require them not to spark when struck with another metal. This makes them useful in the transport and handling of items such as explosives, fuels, and flammable materials. Bronzes are often used in statues and can be seen to form the familiar green oxidized coating.

  • Silver: Mainly a natural substance, but mixing with copper creates sterling silver. Used for decorative impact in jewellery and ornaments, and also to solder different metals together. Silver also finds application in photographic films and papers. At one time, it was used to plate mirrors. It is now used in the manufacture of photochromatic lenses. Photochromatic lenses darken when exposed to ultraviolet light. Silver is also used in brazing alloys and long-life batteries. Silver fulminate is used as an explosive. Silver and silver compounds are found in many creams, ointments, and salves used for medicinal purposes. Silver iodide has been used to seed clouds to make rain.

  • White metals include antimony, bismuth, cadmium, lead, tin, and zinc. Of these, lead, tin, and zinc are of primary interest. It is heavy and very soft and is often used in roofing and in batteries. Lead has been used for centuries for plumbing and plumbing-related uses, such as solders, pipe, and fittings. It is easily formed with low heat, corrosion resistant, and ductile. One primary use of lead in the past was as a pigment in lead-based paints. Another prior use for lead was as an octane booster in gasoline as tetraethyl lead. Modern paints and fuels do not contain lead. Lead has been identified as a health hazard and found to be toxic to animals and humans. Lead is used in storage batteries where the battery plates contain high percentages of lead. Due to its high density, it is also used as radiation shielding.

  • Tin: Tin is a major component of solders and pewter (Pewter is a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and sometimes, less commonly today, lead.). It is also used as both an alloying element and plating material. Tin is a major alloy of many copper products. It is used to plate other metals due to its corrosion resistance.

  • Zinc: Zinc is commonly used as a plating material for steels. This product is termed galvanized steel. It is the familiar grayish coating seen on products such as nails and sheets. It is also used in die castings (such as die-cast children’s toys, carburetor bodies, and pump housings) and as an alloying element in nonferrous metals. Zinc oxide is used in paints, glass, cements, and medicines.

  • Platinum is found in a group of six metals extracted from nickel ores - Iridium, Osmium, Palladium, Rhodium, Ruthenium and Platinum. Of these, platinum has the most widespread application. It is used in corrosion-resistant coatings, as a catalyst for chemical reactions, high-resistance furnace wire, and in catalytic converters. A large percentage of Platinum is used in laboratory equipment, medical instruments, and fine jewelry. Platinum is more expensive per pound than gold.

  • Magnesium: Magnesium is a light material, lighter than aluminum, derived primarily from seawater. Magnesium is a very active metal and, when burned, gives off an intense heat and light. It is used as an alloying element in steels and in applications which require high strength-to-weight ratios, such as extension ladders, aircraft, space vehicles, power tools, and similar applications.

  • Chromium: Chromium is often used in decorative and corrosion-resistant coatings. It is a major alloying element in many steels, especially stainless steels. It is used to provide a tough, wear-resistant, corrosion-resistant, decorative surface.

  • Nickel: Nickel is used as a plating material. It polishes to a high luster. It offers a wide working temperature range. It is also used as an alloying element for other materials, such as steels and bronzes. Nickel is also used in magnets, heating elements, thermocouples, and rechargeable batteries. Nickel and nickel silver are used in jewelry and coins.

  • Refractory Metals: These metals have melting temperatures above 2000 \(^\circ\)Celsius. Some of these approach 3500 \(^\circ\)Celsius. They include such metals as iridium, osmium, and ruthenium, in addition to, chromium, columbium, hafnium, molybdenum, niobium, rhenium, tantalum, tungsten, and vanadium. They find application where high temperature stability is required. For example, furnace components, high speed tools, temperature-measuring devices and components, aircraft components and space vehicle shields. These metals also find application in electrical devices such as capacitors and rectifiers.

  • Titanium: Titanium is lightweight and strong. It is an important metal for the aerospace industry which requires high strength under extreme conditions. It is also used in the medical field for instruments and artificial joint replacements. Titanium is also used as a pigment in paints

  • Antimony is used in solders and as an alloying element in nonferrous metals. The same may be said for bismuth which has the lowest thermal conductivity of any metal except mercury.

  • Cadmium is used as a plating material, as a component of rechargeable batteries (Nickel-cadmium batteries), and as a neutron absorber in control rods for nuclear power plants.

  • Zirconium is also used in nuclear reactor structures and fuel shielding due to its low neutron absorption.

Solved Examples

Solved Example:

53-2-01

The major difficulty during welding of Aluminum is due to its: (GATE ME 2014- Shift I)

Correct Answer: B

Solved Example:

53-2-02

Solder is an alloy consisting of: (NPCIL Stipendiary Trainee ME 2018)

Correct Answer: B

Solved Example:

53-2-03

Brass (alloy of copper and zinc) is an example of:

Correct Answer: A

Solved Example:

53-2-04

Brass contains: (APPSC Group 4 GS 2012)

Correct Answer: A

Solved Example:

53-2-05

Which one of the following metals would work-harden more quickly than the others?

Correct Answer: B

Solved Example:

53-2-06

The usual composition of a soldering alloy is: (Combined Defense Services- 02/14 Nov 2021)

Correct Answer: A

Solved Example:

53-2-07

Which of the following is used for bearing liner?

Correct Answer: D

Solved Example:

53-2-08

Bronze contains:

Correct Answer: B

Solved Example:

53-2-09

Gun metal contains:

Correct Answer: C

Solved Example:

53-2-10

Which is false statement about properties of aluminum?

Correct Answer: B

Solved Example:

53-2-11

Which of the following alloys does not have copper as one of the constituents?

Correct Answer: D

Solved Example:

53-2-12

Constantan an alloy used in thermocouples is an alloy of: (SSC CGL March 2020- Shift II)

Correct Answer: D

Solved Example:

53-2-13

The transistor is made of:

Correct Answer: D