Wetting of stressed grain boundaries in polycrystals and rheological behaviour of resulting materials

Orientational patterns of wetted grain boundaries (GB's) in stressed NaCl polycrystals have been used for describing the GB penetration process on the basis of combined interfacial and mechanical energy balance considerations. The response of the internally wetted polycrystals to static loading has been shown to obey "pressure solution" constitutive laws involving dissolution at stressed surfaces, diffusive transport of dissolved matter and precipitation at less stressed surfaces. Direct experimental evidence for pressure solution mechanism is presented.