Effects of homogenization treatment on precipitated phase in 3003 alloy with high Mn and microstructure as well as mechanical properties of the composite plates were investigated by electrical conductivity measurement

tensile test

metallographic observation and SEM analysis.The results show that the grain size in composite plate is mainly controlled by the combination role of size and density of the precipitated phase

and the inhibition effect of quantity density on recrystallization is the greater than that of size.With the increase of the heating rate of homogenization

the precipitated phase can’t be precipitated by the nucleation

so the number of precipitates is decreased and the size is coarsened.At 200℃/h

the grain size reaches the smallest value and yield strength reaches 71.8 MPa.With the increase of homogenization temperature

the solid solubility of Mn is increased

and the fine precipitates are redissolved

resulting in the decrease of density of precipitates

and increase first and then decrease of the size.At 600 ℃

the yield strength is 64.2 MPa.In addition

the yield strength of the composite plate is decreased after brazing.