What is engineering material and its properties?

Mechanical Properties of Engineering Materials

 Engineering material paly a vital role in this modern age of science and technology Various kind of material are used in industry to meet the requirement of human beings. The selection of a specific material for a particular use is a very complex process. However, one can simplify the choice if the details about (1) use parameter (2 )manufacturing process (3) functional requirement (4) Cost consideration are known. while selecting material for engineering purposes, properties such as impact strength, tensile strength and hardness indicate the suitability for selection but the design engineer will have to make sure that the radiography and other properties of the material are as per the specification.

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The knowledge of material and their properties is of great importance for a design engineer. A design engineer must be familiar with the effects which the manufacturing processes and heat treatment have on the properties of the materials. The engineering materials are mainly classified as 

1. Metals and their alloys , such as iron, steel, copper, aluminium etc.

2. Non-metals, such as glass, rubber, plastic, etc.

The metals may further be classified as

1. Ferrous metals - The ferrous metals are those which have the iron as their main constituent, such as cast iron, wrought iron and steel.

2. Non- Ferrous metals - The non-ferrous metals are those which have a metal other than iron as their main constituent, such as copper, aluminium, brass, tin, zinc, etc.

The important mechanical properties 

Tensile Strength - This enables the material to resist the application of  a tensile force. The internal structure of the material provide the internal resistance to withstand the tensile force. Ultimate strength is the unit stress: measures in Kgf per square millimeter, developed in the material by the maximum slowly applied a load that material can withstand without rupturing in a tensile test.

Shear Strength - It is the ability of a material to resist the shear force applied to the material compressive strength. It is the ability of a material to withstand pressures acting on a given plane.

Elasticity: - It is the property of  material due to which it returns to its original shape and size after releasing the load. Any material that is subjected to an external load is distorted or strained. Elasticity stressed material return to their original dimensions when the load is released.

Hardness - It is the degree of resistance to indentation, scratching abrasion, and wear. Alloying techniques and heat treatment help to achieve the same.

Ductility ;- This is the property of a metal by virtue of which it can be drawn into wires or elongated before rupture take place. It depends upon the grain size of the metal crystals.

Malleability - It is the property of a metal to be deformed or compressed permanently into the sheet without fracture. It shows the ability of the material to be rolled or hammered into thin sheets.

Impact Strength - It is the energy required per unit cross-sectional area to fracture a specimen. It is a measure of the response of a material to shock loading.

Toughness - It is the  ability of the material to absorb energy before fracture or rupture. It may be presented as impact strength of the material.

Brittleness - The term "brittleness" implies sudden failure. It is the property of breaking without warning without visible permanent deformation.

Wear resistance - The ability of a material to resist friction wear under particular conditions to maintain to physical dimensions when in sliding or rolling contact  with a second member.

Corrosion Resistance - Those metals and alloys which can withstand thro corrosive action of a medium corrosion process proceed in them at a relatively low rate that are termed as corrosion- resistance.

Density -This is an important factor of a material where weight and thus the mass is critical aircraft components.



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