Positron lifetime technique have been applied to study lattice defects in industrial aluminium samples. Isochronal annealing up to 550 degreesC reveals recovery in three stages after plastic deformation. Quenching from 400 degreesC to -196 degreesC results in a different annealing behavior compared to the one after plastic deformation indicating the formation, indicating the formation of vacancy clusters between room temperature (RT) and 100 degreesC followed by their annealing between 100 and 400 degreesC. The results are discussed in the frame of the two state trapping model and the positron affinity calculations for different impurities.