CAST AND HOMOGENIZED STRUCTURE OF AL-ZN-MG-CU ALLOYS BY LOW FREQUENCY ELECTROMAGNETIC DIRECT CHILL CASTING

摘要

As cast and homogenized structures of super high strength aluminum Al-Zn-Mg-Cu alloys produced by low frequency electromagnetic casting (LFEC) were discussed. Solidification structure constituents of alloys were first discussed, in particular, boundary phases formed mostly by eutectic reaction were discussed: MgZn_2 included with Cu is a major eutectic phase in boundaries and others are Al_7Cu_2Fe, Mg_(32)(Al, Zn)_(49) and Al_2CuMg formed by microsegregation. Homogenized microstructure for 10 hr at 460°C was lastly discussed.