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Center for Nonlinear Studies |
A deforming solid, containing huge numbers of dislocations, is an intrinsically chaotic system that must on average be moving toward states of increasing probability. In other words, some form of the second law of thermodynamics must be applicable. The relevant thermodynamics, however, must be expressed in terms of the effective temperature of the dislocations, and not the ordinary kinetic temperature of the lattice in which they are moving. An effective-temperature theory, with only a very small number of physics-based parameters, and with several unorthodox physical assumptions, fits experimental, stress versus strain-rate data for Cu for temperatures ranging from cryogenic to about half the melting point, and for fifteen decades of strain rates including results deduced from strong-shock measurements. This theory also provides an accurate account of strain hardening.
Host: Turab Lookman, txl@lanl.gov, 5-0419