Abstract: The major phases in the Cu-rich alloys containing Co,Cr and Si are α-Cu(a solid solution of Co,Cr and Si in Cu),χ-phase(Co_5Cr_3Si_2)and Co_2Si.In comparison with reference sample,it has been detected that the crystal structure of Co_5Cr_3Si_2 is cubic,α-Mn type with a=0.8694 nm.The melting temperature of χ-phase and the alloy are higher than that of the pure Cu,namely,1535 and 1389 K respectively.During ageing treatment,the Co_2Si phase precipitates out from α-Cu and χ-phase simultaneously,but the hardening effect is mainly contributed by the precipitation from α-Cu.

Key words: Cu-rich alloy, X-phase