Investigation on fluidity, anodizing and tensile properties of Al–Mn alloys for application in thin-wall cast components

The molten eutectic Al–Mn alloy, whose eutectic point is about 2.0 wt%, possesses sound fluidity that might satisfy the demands of the thin-wall parts of 3 C products and the auto industry. In this research, the anodic oxide film, fluidity of the melts and tensile property of Al–Mn alloys with additional manganese amounts ranging from 0.6 wt% to 2.7 wt% were studied. The x-ray diffraction test was carried out for the identification of the phases in the fabricated Al–Mn alloys. The commercial ADC12 alloy was selected for comparison of performance. The identical anodic oxidation process and the coloring process were implemented on both the commercial ADC12 alloy and Al–Mn alloys, and the effects on their micro- and macro-structures were observed. According to the results of the spiral fluidity tests, the fluidity length of the molten Al-2.0Mn alloys was close to that of the commercial ADC12 alloy. And the optimal ultimate tensile strength of the Al–Mn alloys was obtained at a manganese content of 2.0 wt%. In addition, analysis on the benchmarks of color difference, film thickness and roughness showed that the appearance quality of anodic oxide film of the Al–Mn alloys was superior to that of the commercial ADC12 alloy. Moreover, as for the Al–Mn alloys, the benchmarks of color difference and roughness of these anodic oxide films were raised with the increase of manganese contents.