[Back]

B. Sonderegger, E. Kozeschnik, C. Sommitsch:
"Modeling particle distances of prolate- and oblate shaped precipitates";
Keynote Lecture: THERMEC 2011, International Conference on PROCESSING & MANUFACTURING OF ADVANCED MATERIALS Processing, Fabrication, Properties, Applications, Quebec - Canada; 2011-08-01 - 2011-08-05; in: "THERMEC 2011", Materials Science Forum / Trans Tech Publications, 706-709 (2012), ISSN: 1662-9752; 1521 - 1526.

In a wide range of materials, precipitation hardening is the key for optimizing properties such as
strength or creep performance. In order to model strengthening effects with physically based
concepts, precipitate kinetic simulations have to be linked to micromechanical models. Part of this
link is the precipitate distance distribution in the glide planes of dislocations. Recently, a new model
for the calculation of distance distributions has been introduced, which is specially designed for
arbitrary size distributions and, thus, capable of handling more realistic microstructures when
compared to classical approaches. Up to now, this model has been restricted to spherical
precipitates. In this work, the model is advanced to account for all kinds of spheroids, that is,
ellipsoids with rotational symmetry. Any prolate, oblate or globular precipitate shape can be
represented by a specific shape factor, or aspect ratio, and an effective radius. The result is
represented in the form of a multiplicative factor for particle distances depending on the aspect ratio
only, and can be expressed as a single explicit formula. It is shown, that prolate shape is most
effective for minimizing particle distances in glide planes, followed by oblate shape and finally
spheres. Since numerous precipitate types feature needle- or platelike shapes, the present model
offers a wide field of applications.

http://dx.doi.org/10.4028/www.scientific.net/MSF.706-709.1521