Kinetics of coherent order-disorder transition in $A{l}_{3}Zr$

Abstract

Within a phase field approach which takes the strain-induced elasticity into account, the kinetics of the coherent order-disorder transition is investigated for the specific case of $A{l}_{3}Zr$ alloy. It is shown that a microstructure with cubic $L{1}_2$ precipitates appears as a transient state during the decomposition of a homogeneous disordered solid solution into a microstructure with tetragonal $D{O}_{23}$ precipitates embedded into a disordered matrix. At low enough temperature, favored by a weak internal stress, only $L{1}_2$ precipitates grow in the transient microstructure preceding nucleation of the $D{O}_{23}$ precipitates that occurs exclusively at the interface of the solid solution with the $L{1}_2$ precipitates. Analysis of microstructures at nanoscopic scale shows a characteristic rod shape for the $D{O}_{23}$ precipitates due to the combination of their tetragonal symmetry and their large internal stress.

2 postscript figures and 1 JPG page

Cited by in corpus (1)

• Microscopical derivation of Ginzburg-Landau-type functionals for alloys and their application to studies of antiphase and interphase boundaries