Engineer must have to know

  • Hardness:- hardness is defined as a property of a material which resist any permanent (Plastic) deformation such as indentation, penetration, scratching, abrasion by a harder bodies. It is measured by the resistance of the metal which it offers. The hardness of the metal is determined by comparing its hardness with ten standard material.

  • Toughness:- The total energy absorb up to fracture point is known as toughness. Toughness is also defined as the resistance of a material against failure. Tenacity and hardness of a metal are the measures of its toughness. It has been found that the value of toughness fall with the rise in temperature. Toughness of the material is indicated by the total area under the material tensile stress-strain curve up to the point of fracture.
  • Stiffness:- Stiffness is defined as the resistance against plastic deformation. Modulus of elasticity is a measure of stiffness of metal. The stiffness of a metal has great importance while selecting it for a member or a component of a machine or a structure. It is also used in graduating spring balance and spring controlled measuring instrument.
  • Creep:- Creep is the phenomena of loosing mechanical property on a constant load by the function of temperature and time. It is important only at elevated temperatures. Generally creeps occurs in steel at higher temperature. The creep is always considered while designing I.C. engines, Turbines etc. Creep has great importance in nuclear reactor field, white metal bearing etc.
  • Ductility:- The ability of a material to undergoes plastic deformation without fracture, to convert in the form of wire on the application of tensile load. It depends upon the grain size of the metal crystals. Ductility may be expressed as percentage elongation or percentage area reduction. example:- Gold, platinum, silver, iron, copper, aluminium, etc.

  • Brittleness:- Brittleness is defined as a material get fails without any significant permanent deformation than the material is called brittle material and property is called brittleness. A brittle material will fracture with little permanent deformation. A brittle material is hard and has little ductility. Cast iron, glass, and concrete are the example of a brittle materials. 
  • Stress:- It is defined as the force of resistance per unit area. It is the internal resistance set up by the molecules of a material to the deformation due to the application of external force.
  • Strain:-  Strain is defined as a deformation per unit length of body. It is also called axial strain, linear strain or longitudinal strain. 
  • Plasticity:- If a material undergoes permanent deformation when load are applicable or apply, then the phenomena is called plasticity. plastically deformed material does not change dimension after removal of load.
  • Elasticity:- If a material get deform on the application of external load and regain its shape and size on the removal of load, then the material is called elastic material and the property is called elasticity. Example:- Rubber, etc.

  • Resilience:- The capacity of a material to absorb a energy with in the elastic limit is known as resilience.
  • Isotropy:- The material which shows same mechanical property in every direction known as isotropic material and the property is known as isotropy.
  • Anisotropy:- If the material shows variation in property along the different direction, the material is called anisotropic material and property is known as anisotropy.
  • Strength:- Strength is a mechanical property of a material. It is defined as ability to sustain failure under the action of applied load.

No comments