Fractographic and micrographic observations of tensile fractured Cu-(9-x)Ni-xMn-6Sn alloys

摘要

In the present study, tensile fracture behavior ofCu-(9-x)Ni-xMn-6Sn alloys was examined as functions of agingtime and an amount of Mn addition, based on the detailed SEMmicrographic and fractographic observations. Discontinuousprecipitation colonies, consisted of equilibrium α and γ phases,were observed around the grain boundary areas, and the amount ofthese colonies increased with increasing Mn addition and agingtime. For those alloys where the Mn addition was restricted below1%, typical fracture mode was intergranular dimpled rupture. InCu-6Ni-3Mn-65n alloys, on the other hand, first cracks occur atdiscontinuous precipitation colonies and, the cracks appear tocoalesce through void sheeting mechanism with the presence ofstrong shear stress between cracks.