alloys and their properties

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1. ALLOYS AND PROPERTIES OF SOME COMMON ALLOYS   DEFINITION: An alloy is a metal (parent metal) combined with other substances (alloying agents),resulting in superior properties such as; strength, hardness, durability, ductility, tensile strength and toughness. Example , mild steel is 0.1 - 0.3% Carbon and 99.9 - 99.7% Iron . Alloys are sometimes described as a mixture of two or more metals. However, this is misleading, as often alloys are composed of just one metal, as well as other non-metal elements. Cast iron is an example, as it is a combination of iron (metal) and carbon (non-metal ). .

2. Metal alloys have specific enhanced properties compared to their ‘parent’ metals For example, steel. Steel is itself an alloy of iron and carbon. Iron is a very brittle metal, likely to break or snap if it receives a sudden blow/shock. Adding the alloying agent carbon, gives the new property of toughness and tensile strength. Steel can be used in the construction industry for bridges and large buildings. A bridge manufactured only from the parent metal, iron, would eventually collapse due to its inability to absorb shocks/blows. The table below gives three alloying elements that can be added to the alloy steel, to further improve its physical properties.

3. Sr.NO Alloying Agent Properties Uses 1 CHROMIUM Resists wear and increases corrosion resistance. Increases hardness and toughness Stainless Steel :Kitchen utensils, medical instruments 2 VANADIUM Increased strength and toughness of steel, including wear resistance Crank shafts ,some hand tools. surgical instruments 3 NICKLE Increased strength and hardness, resistance to corrosion. Engine parts, turbine blades measuring tabes

4. Properties of Brass Brass is a metal made of copper and zinc, having a muted yellow color, somewhat similar to gold. Brass Properties Some of the useful properties of brass include: Relatively resistant to tarnishing Good malleability Good acoustic properties Decorative golden color Relatively low melting point and flow characteristics make it a relatively easy to cast Nonmagnetic Low coefficient of friction   Applications of Brass Brass is often used for: Musical instruments, Lamps, Knobs, Handles, Bowls, Bearings, Sleeves, Bushings, Nuts and bolts, Gears, Valves, Plumbing, Electrical devices, Bells, Hinges, Clock hands, Gibs , Slides, Machine tool components and Zippers.

5. Properties and Uses of Bronze Bronze is a metal alloy consisting primarily of copper and other metals with tin as the main additive . It is an extremely malleable and durable alloy , and can last for years. Bronze is less brittle than other metals, like iron and steel . Bronze is also tremendously weather-resistant and does not rust when exposed to moisture. It is often used in modern architecture , especially for railings and grills, which gives many public buildings an air of grandeur and charm. Bronze is also the alloy of choice in the casting of public, outdoor statues. Its malleability makes it ideal for pouring into elaborate moulds and has a distinguished aesthetic finish. Other variations of bronze are common in other industries: alpha bronze , which is commonly used in the manufacture of coins, fine blades and turbines ; and bismuth bronze , used in light reflectors and mirrors.