The Experimental Investigation Of Isothermal Section Of The Al-Cu-Mn System At 600? And 500?

The isothermal section of the Al-Cu-Mn system at 600? and 500? were investigated over the whole composition range by means of X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM/EDS). The liquidus tempera(?) invariant reactions of some key alloys were determined by differential thermal analysis (DSC). Two new ternary compounds ?4 and ?5 were first discovered in this work. Single-phase alloy for ?4 was prepared successfully and its XRD pattern was obtained. ?4-Al61.8Cu34.4Mn3.8 has a Face-centered cubic crystal structure with space group Fm-3m (NO.225), the lattice constants a=5.8270393(A), and crystallizes with AlCu2Mn structure type. The XRD pattern for ?5-Al68Cu2oMn12 was obtained, but its crystal structure has not been determined. Four ternary compound ?1,?2, ?3, and ? which reported in literature were confirmed in this work and ?3 only observed in 500?. And their homogeneity range at 600? and 500? were determinded in this work. Eight binary phases AlgMn5, (?Mn), Al4Cu9, LT-Al11Mn4, R-Al4Mn, AlCu_?, AlCu_?1(AlCu_?2) and AlCu_? were observed to dissolve the third element. Beside, the solid (Cu) phase composition range was determined also.