Abstract: Cu-C3.3%-Ti13.3% and Cu-Cu02.5%-Al11. 1% powders were mechanically alloyed. The experimental results show that XRD-pattern Peak of carbon vanished and that of Ti,Al and CuO decreased obviously in the powers after milling for 20h. In both powders, Cu-based supersaturated solid solutions were formed ther after milling for 60h. The partial precipitation of Ti、C、Al、O solute elements led to the production of TiC and Al₂O₃ after milling for 100h. Powder refinement and emergence of defects such as subinterface and dislocation induced by mechanical alloying, are main causes of formation of supersaturated solid solution and precipitation of secondary phase.