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

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

Received: 28 March 2000
Accepted: 24 August 2000

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.