Search results
Results From The WOW.Com Content Network
Work hardening, also known as strain hardening, is the process by which a material's load-bearing capacity (strength) increases during plastic (permanent) deformation. This characteristic is what sets ductile materials apart from brittle materials. [1] Work hardening may be desirable, undesirable, or inconsequential, depending on the application.
The strain hardening exponent (also called the strain hardening index), usually denoted , is a measured parameter that quantifies the ability of a material to become stronger due to strain hardening. Strain hardening (work hardening) is the process by which a material's load-bearing capacity increases during plastic (permanent) strain, or ...
Here, n is the strain-hardening exponent and K is the strength coefficient. n is a measure of a material's work hardening behavior. Materials with a higher n have a greater resistance to necking. Typically, metals at room temperature have n ranging from 0.02 to 0.5. [3]
As the models are purely empirical, it is often useful to try different models and check which has the best fit with the chosen material. The Ramberg-Osgood equation can also be expressed using the Hollomon parameters [3] where is the strength coefficient (Pa) and is the strain hardening coefficient (no units). [4]
The amount of strain in the stable neck is called the natural draw ratio [6] because it is determined by the material's hardening characteristics, not the amount of drawing imposed on the material. Ductile polymers often exhibit stable necks because molecular orientation provides a mechanism for hardening that predominates at large strains. [7]
In continuum mechanics, elastic shakedown behavior is one in which plastic deformation takes place during running in, while due to residual stresses or strain hardening the steady state is perfectly elastic. Plastic shakedown behavior is one in which the steady state is a closed elastic-plastic loop, with no net accumulation of plastic deformation.
Note that this is an empirical relation and does not model the relation at other temperatures or strain-rates (though the behavior may be similar). Generally, raising the temperature of an alloy above 0.5 T m results in the plastic deformation mechanisms being controlled by strain-rate sensitivity, whereas at room temperature metals are ...
For this reason, deep drawing sheets are often cold rolled in advance to prevent the formation of stretcher-strain marks during the actual deep drawing process. [6] The formation of Lüder bands can occur again with a deformation over time, since the interstitial atoms accumulate by diffusing processes called precipitation hardening (or aging).