Precipitation in Age-hardening alloys
1. Precipitation in Al-Cu alloys
2. Precipitation in Al-Ag alloys
Precipitation in Al-Cu alloys
-phase (Cu Al2) is the equilibrium phase
Quenched and ageing @ temp.
Sequence of Precipitation
a) Explain the differentiating criterion between high and low angle grain boundaries.
b) What is the necessary condition for equilibrium between different phases? Explain using free 2
energy curves of the phases.
Why melting occurs at equilibrium
Overall Transformation Kinetics TTT Diagram
To introduce concept of phase transformation kinetics as
described by the Kolmogorov-Johnson-Mehl-Avrami equation
(t,T) - fraction transformed as a function of
time and temperature, depends on
Usually treated constant (1 atm.) in
solid state transformations
Gibbs free energy of pure A