Materials Engineering Properties Quiz

Mechanical Properties of Materials

• Strength is the ability of a material to bear a load before fracture.

Ductility

• Ductility is the extent of permanent or plastic deformation that a material undergoes before fracture.
• There are two measures of ductility: percentage elongation and percentage reduction in area.

Elasticity

• Elasticity is the ability of a material to restore its original shape and size after removal of external deforming loads.
• Young's modulus is the measure of elasticity.

Stiffness

• Stiffness is the resistance to elastic (or recoverable) deformation.

Hardness

• Hardness is the resistance to plastic (or permanent) deformation, which includes indentation, scratching, or marking.

Toughness

• Toughness is the resistance to both elastic and plastic deformation.

Fatigue

• Fatigue is the permanent deformation and/or failure of a component when subjected to fluctuating (both in magnitude and direction) loads.
• Examples of fatigue include gear teeth, aircraft wings, and crankshaft of an automobile.

Fracture

• Fracture is the splitting of a component into at least two halves.

Creep

• Creep is the permanent deformation and/or failure of a component when subjected to high stresses at high temperature.
• Example of creep includes turbine disk and blades.

Stress-Strain Relationships

• There are three types of static stresses to which materials can be subjected: tensile, compressive, and shear.
• Tensile stress tends to stretch the material, compressive stress tends to contract the material, and shear stress tends to cause adjacent portions of the material to slide against each other.
• A stress-strain curve is the basic relationship that describes mechanical properties for all three types of loading.