Hot bands of a continuous cast aluminum alloy（AA2037） with and without 70% cold rolling deformation were annealed at high temperatures（470 ℃）.The recrystallization microstructure and precipitation in the samples after annealing were investigated by positron lifetime and coincidence Doppler broadening techniques.The experimental results showed that positron mean lifetime decreased with increasing annealing time due to the formation of the precipitations（T phase） and recovery of defects induced by hot-rolling and/or 70% cold-rolling.Furthermore

coincidence Doppler broadening（CDB） ratio curve observed that characteristic shape peak of Mn and Cu increased with annealing time

i.e.the content of the T phase

which identified that there exist Mn and Cu elements in T phase.