Aa. Elvin et Ss. Sunder, MICROCRACKING DUE TO GRAIN-BOUNDARY SLIDING IN POLYCRYSTALLINE ICE UNDER UNIAXIAL COMPRESSION, Acta materialia, 44(1), 1996, pp. 43-56
Citations number
28
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
This paper examines grain boundary sliding as a mechanism for nucleati
on and growth of microcracks in polycrystalline S2 ice, under uniaxial
compression. The loading rate is fast enough so that the polycrystal
response is almost linear. A unit cell model is set up and the resulti
ng boundary value problem solved using the finite element method. Simu
lations show that by allowing grain boundary sliding a defect originat
ing at the triple point grows stably, reaches a critical length and th
en propagates unstably to the neighboring triple point. The influence
of the elastic mismatch between neighboring grains on microcracking st
ress is not strong. The stress causing microcrack growth is found to b
e inversely proportional to the square root of the grain size. If no g
rain sliding takes place, and only the elastic anisotropy mechanism op
erates, the stresses required for microcrack nucleation and growth are
unrealisticly high; the resulting microcracks are also too short.