MECHANICAL PROPERTIES OF ENGINEERING MATERIALS

The important mechanical properties are listed below:

• Tensile strength: This enables the material to resist the application of a tensile force. The internal structure of the material provides the internal resistance to withstand the tensile force. Ultimate strength is the unit stress, measured in kg per square millimetre, developed in the material by the maximum slowly applied 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 on 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. Elastically stressed materials 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 takes 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, i.e., it is a measure of the response of a material to shock loading.
• Toughness: It is ability of a 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, i.e., without visible permanent deformation.
• Wear resistance: The ability of a material to resist friction wear under particular conditions, i.e., to maintain its physical dimensions when in sliding or rolling contact with a second member.
• Corrosion resistance: Those metals and alloys which can withstand the corrosive action of a medium, i.e., corrosion processes precede in them at a relatively low rate are termed corrosion-resistant.
• Density: This is an important factor of a material where weight and thus the mass is critical, i.e., aircraft components.