Propertiesmechanical

Propertiesmechanical, more commonly called mechanical properties, describe how a material responds to external forces and deformations. They are intrinsic to composition and microstructure and are influenced by temperature, rate of loading, and environmental conditions. Common mechanical properties include strength, stiffness, ductility, hardness, toughness, and resistance to time-dependent effects such as creep and fatigue.

Strength refers to the stress a material can withstand before permanent deformation; yield strength is where plastic deformation begins, and ultimate tensile strength is the maximum stress before failure. Stiffness is quantified by Young's modulus, showing resistance to elastic deformation. Ductility measures the extent of plastic deformation before fracture, typically reported as elongation or reduction of area. Hardness relates to resistance to localized plastic deformation, assessed by hardness tests such as Rockwell, Brinell, or Vickers.

Toughness is the amount of energy a material can absorb before fracture, represented by the area under the stress-strain curve. Fatigue strength describes performance under repeated loading; creep strength describes resistance to slow, time-dependent deformation at temperature. Fracture toughness indicates resistance to crack propagation. Poisson's ratio is sometimes included as a measure of transverse response to axial strain.

Mechanical properties are determined via standardized tests, including tensile tests, compression tests, hardness tests, Charpy or Izod impact tests, fatigue tests, and creep tests. Results depend on material state: heat treatment, strain rate, grain size, porosity, and impurities.

Understanding these properties guides material selection and design for applications ranging from structural components to microelectronics.