Solid solution decomposition and Guinier-Preston zone formation in Al-Cu alloys : A kinetic theory with anisotropic interactions

• Using methods of statistical kinetic theory parametrized with first-principles interatomic interactions that include chemical and strain contributions, we investigated the kinetics of decomposition and microstructure formation in Al-Cu alloys as a function of temperature and alloy concentration. We show that the decomposition of the solid solution forming platelets of copper, known as Guinier-Preston (GP) zones, includes several stages and that the transition from GP1 to GP2 zones is determined mainly by kinetic factors. With increasing temperature, the model predicts a gradual transition from plateletlike precipitates to equiaxial ones and at intermediate temperatures both precipitate morphologies may coexist.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Dynamics of phase separation

First order phase transitions

Kinetic theory

Phase diagrams

Phase separation

phase transition by order

Spinodal decomposition

Structural order parameter

Alloys

Solid solutions

Lattice models in condensed matter

Mean field theory

Statistical methods

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