Al-4%Cu Precipitates
Sequence of precipitates is formed. Those which form first have the lowest surface energy and are hence easiest to nucleate
?ss initially decompose s to GP zones, layers of copper atoms segregating to particular crystal planes of Al
Next the coherent precipitate ?’’ is formed
Then the semicoherent precipitate ?’ is formed as ?’’ grows
Finally the totally incoherent ? phase, Al2Cu is formed