Abstract

Cu-Sn based alloys were manufactured by gas atomization spray casting route in order to achieve a fine scale microstructure and a high tensile strength. The spray cast Cu-10Sn-2Ni-0.2Si alloy had an equiaxed grain microstructure, with no formation of brittle delta-Cu_41Sn_11 phase. Aging treatment promoted the precipitation of finely distributed particles corresponding to delta-Ni_2Si intermetallic phase throughout the alpha-(CuSn) matrix. The cold-rolled Cu-Sn-Ni-Si alloy had a very high tensile strength of 1200 MPa and an elongation of 5%. Subsequent aging treatment at 450°C for 1h slightly reduced the tensile strength to 700 MPa and remarkably increased the elongation up to 30%. This result has been explained by coarsening the precipitates due to over aging and reducing the dislocation density due to annealing effects.

• Keywords: Spray casting;Cu-Sn;Cu-Sn-Ni-Si;Equiaxed grain;Tensile strength;