Properties of Materials | Mechanical Properties of Materials - News4u95

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Sunday, 28 March 2021

Properties of Materials | Mechanical Properties of Materials

Properties of Materials


A material is that, out of which anything is made. It relates itself to matter.


The knowledge of materials and their properties is of great significance for a design engineer.


The machine elements should be made from such a material which has properties suitable for the operating conditions.


Property of a material is a factor that influences qualitatively or quantitatively the response of a given material under the action of forces, temperatures, pressures, etc.


Property indicates that, whether a material is suitable or unsuitable for a particular use in industry.


The material property is independent of the dimension or shape of the material.


The various material properties are divided into following groups:

  1. Mechanical properties of Materials
  2. Thermal properties of Materials
  3. Electrical properties of Materials

 

Mechanical Properties of Materials


Mechanical properties include those characteristics of material that describe its behaviour under the action of external forces.


The knowledge of mechanical properties of materials is very essential in order to construct a mechanically fool-proof structure.


Mechanical Properties of Materials
Mechanical Properties of Materials


Some of the important mechanical properties are as follows:

 

Elasticity  

  • It is the property of material to regain its original shape after deformation when the external forces are removed.
  • This property is required for materials used in tools and machines.
  • It is important to note that, steel is more elastic than rubber.

 

Plasticity

  • The property of a material which retains the deformation produced under the load permanently is called as plasticity.
  • This property is essential in stamping, press work, forgings, ornamental work, etc.

 

Toughness

  • Toughness is the total amount of energy absorbed by the material before its failure.
  • It is the complete area under the stress-strain curve i.e. summation of elastic and plastic region.
  • This properly is essential in parts subjected to shock and impact loads.

 

Resilience

  • Resilience of a material is defined as the total amount of energy absorbed by the material during its elastic deformation.
  • This property is essential for springs, shock absorbers, etc.
  • The area under stress-strain curve in the elastic region indicates resilience.

 

Strength

  • It is ability of a material to resist the externally applied forces without failure.
  • It is measured in kg/mm' or 1\1/m.m2.

 

Stiffness

  • It is the ability of a material to resist deformation under stress.
  • It is also defined as the force or load per unit deflection. It is measured in N/mm.

 

Ductility

  • It is defined as the ability of a material to undergo plastic deformation under tensile loading, before its fracture.
  • Also ductility is the property of a material by which it can be drawn into fine wires. For example rubber.

 

Malleability

  • It is defined as the ability of a material to be formed by hammering or rolling.  
  • It is the capacity of a material to withstand deformation under compression without failure.
  • The main difference between ductility and malleability is that, the ductility is considered as tensile property and malleability is considered as compressive property.

 

Brittleness

  • It is the property of breaking of a material with little permanent distortion.
  • Brittleness of a material is opposite to ductility. For example glass, concrete block, etc.

 

Hardness

  • It is an important property of metals.
  • It is defined as resistance of metal to plastic deformation usually by indentation.
  • It is also defined as resistance to scratch, abrasion or cutting.

 

Fatigue

  • When a material is subjected to repeated stresses or loading, it fails at stresses below the yield point stress. Such type of failure of material is called as fatigue.
  • Fatigue failure is caused by means of progressive crack formations which are generally of microscopic size.
  • It is considered while designing shafts, gears, springs, etc.

 

Creep

  • When a material is subjected to constant stresses at high temperature for a. long period of time, it will undergo a slow and permanent deformation which is called as creep.
  • It is considered while designing of boilers, I.C. engines, pumps, turbines, etc.

 

Questions Covered in article

Q.1 Define the mechanical properties of materials?

Q.2 Describe any six mechanical properties of materials?

Q.3 Define the following mechanical properties of materials:

a) Malleability b) Resilience c) Toughness d) Hardness

 

 

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