HR: 1330h
AN: C43A-02    [Abstracts]
TI: Grain shape relaxation in elongated grained polycrystalline sample
AU: * Di Prinzio, C L
EM: diprinz@helios.phy.ohiou.edu
AF: Ohio University, Dept. Physics and Astronomy, Clippinger Laboratory, Athens, oh 45701
AU: Wilen, L
EM: wilen@helios.phy.ohiou.edu
AF: Ohio University, Dept. Physics and Astronomy, Clippinger Laboratory, Athens, oh 45701
AB: The evolution of fabric (c-axis distributions) and texture (grain size and shape) in an ice core depends on a variety of physical conditions including, but not limited to, temperature, impurity content, strain rate and strain symmetry. It is interesting to consider the possibility of using grain elongation as an in-situ measure of the strain rate history in a core. In the absence of any processes leading to new grain formation (e.g. polygonization or recrystallization) it may be possible to relate measured grain elongation to the strain history in a simple way. A computer grain growth simulation was used to investigate the shape relaxation of elongated grains in a polycrystalline sample. The program employs only geometrical arguments and uses basic equations for grain boundary migration. The simulation was carried out in a two-dimensional sample with 1000 grains. The initial elongation of each grain was arbitrarily horizontal and the mean elongation was around 30%. The initial grain size of the crystals was normally distributed around of a mean grain size. The evolution of the mean elongation and average grain size of the sample were computed. The average elongation decreases "exponentially" with time as the elongated grains grow and transform into rounded grains. The elongation relaxation process did not affect the linear relationship between the grain size and the time. A simple (empirical) theoretical model, which includes grain growth and strain rate, was compared with the results of the simulation and the free parameters of this model were determined. The empirical model can then be used to study grain growth and elongation under arbitrary conditions of imposed strain.
UR: http://www.agu.org
DE: 1827 Glaciology (1863)
SC: Cryosphere [C]
MN: 2005 Joint Assembly