Kinetics of shock-induced polymorphic phase transitions
Shock-loading induces polymorphic phase transitions in some solids if the pressure exceeds that at which phase transition occurs under quasi-static compression. Volume changes in shock-induced transitions must occur very rapidly to produce the structured shock waves observed, so transition rates are large under these dynamic conditions. By contrast, the same transition might require minutes or hours under quasi-static loading. If shock-induced transition is so rapid that kinetic effects can be ignored, a steady two-wave structure is propagated. The first wave, of amplitude equal to the transition pressure, shocks the material to the phase boundary but produces no transition; the second, slower wave produces the transformed phase. When kinetic effects are important, this two-wave structure does not form immediately but by an evolutionary process which produces transients in the amplitudes and rise times of the stress waves. By measuring these transient effects, some facts about the kinetics of phase transitions have been inferred. Comprehensive studies on phase-transition kinetics in antimony, iron, and potassium chloride are described, with emphasis on a thermodynamic description of the intermediate states during transition. Complicating effects such as shear strength and wave perturbations due to free surfaces are discussed.
- Research Organization:
- Sandia Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 7218908
- Report Number(s):
- SAND-77-0267C; CONF-761204-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Shock loading and unloading in bismuth
Stress wave propagation in rock
Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
360602 -- Other Materials-- Structure & Phase Studies
ALKALI METAL COMPOUNDS
ANTIMONY
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
IRON
MATHEMATICAL MODELS
MECHANICS
METALS
PHASE TRANSFORMATIONS
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
SHOCK WAVES
TRANSITION ELEMENTS