An alloy may be described as a metal having more than one element, the other elements having been added to enhance the base metal's properties to suit a particular application. These properties include resistance to high temperatures and shrinking; a requirement of gas turbine blades for example.
Introduction to Alloys
Alloys have been produced for centuries and are used in domestic, medical, and engineering applications.
Metal alloys are made using several methods, such as adding the element to the base metal in a furnace or by hot press process in which the metal and elements are sandwiched and pressed to form an alloy.
The alloys have many applications in engineering in which high temperature, low corrosiveness, toughness, and durability are required.
This is an article on alloys in which we will examine the elements used to attain the required properties and some of the applications of alloys in engineering, along with some of the benefits of metal alloys.
Images of Sparton Alloy Steel Construction and Phase Diagram for Base Metal Alloys
Elements Used to Produce Alloys
The main alloys produced from base metal cast and carbon steels currently used in engineering include titanium alloys, aluminum alloys, zinc alloys, copper alloys, magnesium and nickel alloys. However, I have listed a few more popular elements below along with the properties they bring to the particular alloy.
- Copper is used along with tin to produce the alloy bronze, whose properties can be modified by altering the amounts of tin and copper added to the steel.
- The main properties of bronze are resistance to corrosion and metal fatigue along with good thermal and electrical conductivity.
- Applications include numerous plumbing fittings, gearing, valves, and piping components.
- Aluminum is one of the most versatile elements available to today’s engineers; however its properties can be further improved by the addition of other elements such as copper manganese and zinc. These improve the aluminium’s strength, hardness, cast-ability and resistance to corrosion.
- The main application is in the transport sector, particularly in the construction of aircraft and railway rolling stock. Aluminum alloys are also used extensively in the car industry in the production of engines and gearboxes.
- Zinc is used along with copper to form brass, and was used exclusively for valves when I was serving my time in Harland & Wolff shipyard in the sixties, where within the engine-works department there was a large dedicated brass valve turning shop.
- However, brass is not as popular in engineering nowadays apart from manufacture of brass fittings on fire hoses, screwed rod and screws, the main application being in the domestic sector and in the production of musical instruments.
- Zinc is also alloyed along with lead and tin to make solder, a low melting point alloy used in soldering.
- Used to produce bronze and solder as previously discussed but also to form the alloy Babbitt, used to line white metal bearings.
- As previously noted, lead is used with tin in the formation of solder alloy. It is also used in the formation of typesets in the printing industry and again in Babbitt white metal alloy production
- The main application of vanadium alloys are high speed tool steels (HSTS). Its properties give a reduction in weight, an increase in tensile strength, and resistance to corrosion. It is also used along with chrome in the formation of hand tools such as spanners and socket sets.
- Chromium is used to produce stainless steel and is known for its resistance to corrosion and hardness properties. Stainless steel has many industrial uses – the main ones being tools, surgical equipment, specialist valves and piping, liquid storage tanks, and structural sections.
- Manganese gives an alloy the properties of hardness without causing brittleness. Applications are the production of railroad tracks, switching points which require the above properties. Manganese is also used to produce a very hard alloy known as Spartan steel being used in the steel construction industry.
- When small quantities of tungsten are added to steel, a very hard-wearing, tough alloy is formed. It has many applications in the military sector both as armor and armor piercing components. It is also used in engineering where high temperatures are prevalent such as gas turbine components and where the properties of toughness without brittleness are a requirement.
- Tungsten alloys are also used in x-ray tubes and incandescent light fittings as well tungsten inert gas welding components, due to its high melting property.
- Nickel is corrosion resistant and it is used along with other elements to form stainless steel, brass and bronze with their attendant properties. Its applications are in power station rotary components which require the alloys properties of resistance to cracking, deformation, corrosion under sustained high temperatures are numerous.
- Nickel alloys are also used in the aerospace and chemical industries.