Europhys. Lett., 52 (2), p. 224 (2000)

Dynamics of mesoscopic precipitate lattices
in phase-separating alloys under external load

R. Weinkamer ^1,2,3 - H. Gupta ^2,3 - P. Fratzl ³ - J. L. Lebowitz ²

 ¹ Institut für Materialphysik der Universität Wien
Strudlhofgasse 4, A-1090 Wien, Austria
 ² Departments of Mathematics and Physics, Rutgers University, Busch Campus
New Brunswick, 08903 NJ, USA
 ³ Erich Schmid Institut für Materialwissenschaft
Österreichische Akademie der Wissenschaften & Institut für Metallphysik
Montanuniversität Leoben - Jahnstraße 12, A-8700 Leoben, Austria

PACS :
81.30.Mh - Solid-phase precipitation
64.75.+g - Solubility, segregation, and mixing; phase separation
02.70.Lq - Monte Carlo and statistical methods

Abstract:

We investigate, via three-dimensional atomistic computer simulations, phase separation in an alloy under external load. A regular two-dimensional array of cylindrical precipitates, forming a mesoscopic precipitate lattice, evolves in the case of applied tensile stress by the movement of mesoscopic lattice defects. A striking similarity to ordinary crystals is found in the movement of "meso-dislocations", but new mechanisms are also observed. Point defects such as "meso-vacancies" or "meso-interstitials" are created or annihilated locally by merging and splitting of precipitates. When the system is subjected to compressive stress, we observe stacking faults in the mesoscopic one-dimensional array of plate-like precipitates.

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