Table 2 Equilibrium values calculated at 453 K and 101 kPa with the nominal composition given in Table 1. The Al matrix and the precipitate β″ were considered as the only active phases

Molar fraction of Mg in the precipitate: \( {\boldsymbol{c}}_{\boldsymbol{\beta}, \boldsymbol{Mg}}^{\ast} \)

0.4545

Molar fraction of Si in the precipitate: \( {\boldsymbol{c}}_{\boldsymbol{\beta}, \boldsymbol{Si}}^{\ast} \)

0.5105

Molar fraction of Al in the precipitate: \( {\boldsymbol{c}}_{\boldsymbol{\beta}, \boldsymbol{Al}}^{\ast} \)

0.0350

Molar fraction of Mg in the matrix:\( {\boldsymbol{c}}_{\boldsymbol{eq},\boldsymbol{Mg}}^{\boldsymbol{\infty}} \)

7.06E-5

Molar fraction of Si in the matrix: \( {\boldsymbol{c}}_{\boldsymbol{eq},\boldsymbol{Si}}^{\boldsymbol{\infty}} \)

8.61E-3

Coefficient of diffusion of Mg in the matrix (m²/s)

2.01E-19

Coefficient of diffusion of Si in the matrix (m²/s)

1.35E-19

Molar volume of the precipitate (m³/mol)

1.048E-5