Search results
Results from the WOW.Com Content Network
The portion where necking occurs may be called the neck of the specimen. In engineering and materials science, necking is a mode of tensile deformation where relatively large amounts of strain localize disproportionately in a small region of the material. The resulting prominent decrease in local cross-sectional area provides the basis for the ...
During necking, the material can no longer withstand the maximum stress and the strain in the specimen rapidly increases. Plastic deformation ends with the fracture of the material. Diagram of a stress–strain curve, showing the relationship between stress (force applied) and strain (deformation) of a ductile metal.
Beyond tensile strength, a necking forms where the local cross-sectional area becomes significantly smaller than the average. The necking deformation is heterogeneous and will reinforce itself as the stress concentrates more at the reduced section. Such positive feedback leads to quick development of necking and leads to fracture.
The work-hardened steel bar has a large enough number of dislocations that the strain field interaction prevents all plastic deformation. Subsequent deformation requires a stress that varies linearly with the strain observed, the slope of the graph of stress vs. strain is the modulus of elasticity, as usual.
Sample deformation mechanism map for a hypothetical material. Here there are three main regions: plasticity, power law creep, and diffusional flow. A deformation mechanism map is a way of representing the dominant deformation mechanism in a material loaded under a given set of conditions. The technique is applicable to all crystalline materials ...
Deformation mechanism maps provide a visual tool categorizing the dominant deformation mechanism as a function of homologous temperature, shear modulus-normalized stress, and strain rate. Generally, two of these three properties (most commonly temperature and stress) are the axes of the map, while the third is drawn as contours on the map.
Strain hardening (work hardening) is the process by which a material's load-bearing capacity increases during plastic (permanent) strain, or deformation. This characteristic is what sets ductile materials apart from brittle materials. [1]
Fracture strength, also known as breaking strength, is the stress at which a specimen fails via fracture. [2] This is usually determined for a given specimen by a tensile test, which charts the stress–strain curve (see image).