Crystals Take a Chill Pill: A Thermomechanical Theory of Low-Temperature Melting
Posted August 21, 2012 10:34 AM
From Phys.org - latest science and technology news stories:
(Phys.org) -- Virtual melting is a phase transition phenomenon associated with solid-solid phase transformation and relaxation of nonhydrostatic stresses and other effects in HMX explosives, as well as with crystal-crystal and crystal-amorphous phase transformation under high pressure. Since its initial formulation by Iowa State University Professor Valery I. Levitas and coworkers, virtual melting has been estimated to occur at 100 - 1000 °K below the material's equilibrium melt temperature. Recently, however, Levitas and University of Texas Associate Professor Ramon Ravelo proposed a new deformation mechanism on which melting can occur at temperatures 4000 °K lower than the equilibrium melt temperature in materials subjected to high deviatoric stresses (where stress components vary by direction, and which control the degree of body distortion) in a shock wave. In addition, they've developed a novel thermomechanical theory of melting that predicts extremely large reduction in melting temperature.