Abstract:Effects of sub-rapid solidification by water-cooling Cu mould on microstructure and mechanical properties of 6061 aluminum alloy with Mn and Zr addition were investigated. Microstructure of the alloys was analyzed by optical microscopy, scanning electron microscopy and EDS energy spectrum. Solubilities of Mg, Si and Mn elements in as-cast and homogenized Al alloys were estimated by X-ray diffraction and Vegard’s Law. Tensile tests were conducted to investigate the mechanical properties of 6061 aluminum alloy. Results showed that both the segregation of Mg, Si and Mn elements and homogenization time were decreased by sub-rapid solidification. The grain size had also been refined significantly by adding Mn and Zr elements. As-cast precipitated phase was transformed into α-Fe phase of granulate from β-Fe of bone and strip by water-cooling Cu mould., and they were maily granular α-Al8(MnFe)2Si和α-Al8(MnFeCr)2Si after homogenization treatment. Tensile properties of Al alloy with Mn and Zr addition casted by water-cooling Cu mould. The UTS, YS and Elongation of homogenized alloy researches to 286Mpa, 27Mpa and 17.84%, respectively.