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U.S. Department of Energy
Office of Scientific and Technical Information

State-variable theories for nonelastic deformation

Technical Report ·
OSTI ID:6654116

The various concepts of mechanical equation of state for nonelastic deformation in crystalline solids, originally proposed for plastic deformation, have been recently extended to describe additional phenomena such as anelastic and microplastic deformation including the Bauschinger effect. It has been demonstrated that it is possible to predict, based on current state variables in a unified way, the mechanical response of a material under an arbitrary loading. Thus, if the evolution laws of the state variables are known, one can describe the behavior of a material for a thermal-mechanical path of interest, for example, during constant load (or stress) creep without relying on specialized theories. Some of the existing theories of mechanical equation of state for nonelastic deformation are reviewed. The establishment of useful forms of mechanical equation of state has to depend on extensive experimentation in the same way as that involved in the development, for example, the ideal gas law. Recent experimental efforts are also reviewed. It has been possible to develop state-variable deformation models based on experimental findings and apply them to creep, cyclic deformation, and other time-dependent deformation. Attempts are being made to correlate the material parameters of the state-variable models with the microstructure of a material. 24 figures.

Research Organization:
Cornell Univ., Ithaca, NY (USA). Dept. of Materials Science and Engineering
DOE Contract Number:
AC02-76ER02172
OSTI ID:
6654116
Report Number(s):
DOE/ER/02172-36; ON: DE83004493
Country of Publication:
United States
Language:
English