20 Important Mechanical Properties Of Material
Mechanical properties of Material
In this whole world materials are mainly categorized into two types :
- Non Metal
Metals are further sub-categorised into two broad classes i.e
- Ferrous metals and
- Non-ferrous metals.
Ferrous metals mainly consist of iron with comparatively small addition of other materials or metals too. Ferrous metals are widely used in mechanical industries for construction, pipelines, in the creation of tools and many more. They are magnetic in nature and shows little resistance to corrosion.
- Mild steel ; Carbon steel ; Stainless steel ; Cast iron ; Wrought iron these all are the example of ferrous Metals.
Nonferrous metals contain little or no iron. They are not magnetic in nature. These metals shows higher resistance to corrosion. Examples are Aluminum, Stainless Steel, Magnesium, Copper, Zinc, Lead, Silver, Brass, Gold etc.
Read Also : Alloys & Its Properties
Most Mechanical Properties are associated with metals these are-
Strength is a measure of how well a material can resist itself to get deformed from its original shape. Also, its an ability of a material to withstand load without failure is known as strength. The higher the force required to change the shape of the material, the stronger the material is. Strength of any material mainly depends on type of loading and deformation before fracture. According to loading types(either compressive or tensile), strength can be classified into three types.
- Tensile strength : is a measure of how well a metal resists being pulled apart
- Compressive strength : or hardness measures how well a material resists being squeezed together.
- Shear strength: is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear.
According to the deformation before fracture, strength can be classified into three types.
- Elastic strength: means that when a body is deformed whether it returns to to its original shape.
- Yield strength : refers to how well a rod or beam of a particular metal resists bending and permanent deformation.
- Ultimate strength : the capacity of a material or structure to withstand loads tending to elongate
A homogeneous material means a material which has uniform composition or properties throughout. Metals, alloys, ceramics etc all are the examples of homogeneous materials. Property is known as homogeneity.
A material which has same elastic properties along its all loading direction known as isotropic material. Isotropy is defined as uniformity of various physical properties in all orientations
A material which exhibits different elastic properties in different loading direction known as an-isotropic material. Simply defined as material have different properties in different directions
If a material regain its original dimension after removal of load, it is known as elastic material and the property by virtue of which it regains its original shape is known as elasticity.
Every material possess some elasticity. It is measure as the ratio of stress to strain under elastic limit.
The ability of material to undergo some degree of permanent deformation without failure after removal of load is known as plasticity. This property is used for shaping material by metal working. It is mainly depends on temperature and elastic strength of material.
Ductility is a property by virtue of which a solid metal can be drawn into wires. It can also define as a property which permits permanent deformation before fracture under tensile loading. The amount of permanent deformation (measure in percentage elongation) decides either the material is ductile or not.
Percentage elongation = (Final Gauge Length – Original Gauge Length )*100/ Original Gauge Length
If the percentage elongation is greater than 5% in a gauge length 50 mm, the material is ductile and if it less than 5% it is not.
Copper, Aluminum, Steel are the example of Ductile Material.
Brittleness is a property by virtue of which, a material will fail under loading without significant plastic deformation in dimension. Glass, cast iron, concrete etc are well known example of brittle materials.
The ability of material to resist elastic deformation or deflection to an applied force, known as stiffness. A material which offers small change in dimension during loading is more stiffer. The more flexible an object is, the less stiff material will be. For example spring is less stiffer
- steel is stiffer than aluminum.
The property of a material to resist penetration or localized plastic deformation by either mechanical indentation or abrasion is known as hardness. It is an ability to resist scratching, abrasion or cutting. It is also define as an ability to resist fracture under point loading. It have strong intermolecular bonds between the molecules.
Toughness is defined as an ability of a material to withstand with plastic or elastic deformation without fracture. It is defined as the amount of energy absorbed before actual fracture.
A property by virtue of which a metal can flatten into thin sheets, known as malleability. It is also define as a property which permits plastic deformation under compression loading.
A property by virtue of which a material can be cut easily.
The ability of metal to dissipate the energy of vibration or cyclic stress is called damping. Cast iron has good damping property, that’s why most of machines body made by cast iron.
The slow and progressive change in dimension of a material under influence of its safe working stress for long time is known as creep. Creep is mainly depend on time and temperature. The maximum amount of stress under which a material withstand during infinite time is known as creep strength.
The amount of energy absorb under elastic limit during loading is called resilience. The maximum amount of the energy absorb under elastic limit is called proof resilience.
#17. Fatigue Strength:
The failure of a work piece under cyclic load or repeated load below its ultimate limit is known as fatigue. The maximum amount of cyclic load which a work piece can bear for infinite number of cycle is called fatigue strength. Fatigue strength is also depend on work piece shape, geometry, surface finish etc.
The loss of ductility of a metal caused by physical or chemical changes, which make it brittle, is called embrittlement.
#19. Impact strength:
The ability of a material to resist impact without shattering.
#20. Fatigue limit:
Maximum stress a material can withstand under repeated loading (MPa).
ArticleSource : Wikipedia