Abstract:The effects of hydro co-extrusion on the microstructure changes of aluminum hybrid duo-cast Al 3003/Al 4004 clad materials were studied. The specimen of duo-cast Al 3003/Al 4004 clad materials was in circle shape, and was composed of Al 3003(outside) and Al 4004(inside) materials. The specimen was extruded by the hydro co-extrusion equipment. The manufacturing conditions of the specimen were 423 K in temperature and 5 in extrusion ratio. The dimensions of the specimen were 80 mm in diameter of the Al 4004 material and 35 mm in thickness of the Al 3003 material before the hydro co-extrusion process, and 30 mm in diameter and about 5 mm in thickness after the extrusion process, respectively. The microstructure and the hardness for two specimens were investigated. The hardness value of cross section in the duo-cast Al 3003/Al 4004 clad materials before the extrusion process was increased in form of the parabola toward the center. However, after the extrusion process, it was almost constant in the portion of Al 4004 material. Lots of big voids above 1 mm in diameter in the specimen existed in the interfacing region of Al 3003 and Al 4004 materials before the extrusion process. These big voids disappeared after the process of hydro co-extrusion.

Key words: clad materials; hydro co-extrusion process; duo-casting; microstructure