摘要
By using ICP spectroscopy, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction, SEM and microscope analysis, the effects of Mn on the structure of B319 aluminum alloy are studied. The results show that without the addition of Mn, there are coral-like Al_2Cu phase and needle-like β-Fe (Al_5FeSi)in the structure of casting with lost foam casting (LFC). Precipitation of Al_2Cu can take place along the long sides of the β needles. Under the rapid cooling rates, such as ones in metallic mold, the Fe phase appears in the form of Chinese script α-Fe. With the addition of Mn, there are Chinese script α-Fe phases(Al_(15) (Mn, Fe)_3Si_2)in the structure of LFC casting. When Fe/Mn≤1.5, the needle-like β-Fe phases transform to Chinese script α-Fe completely. With the decrease of Fe/Mn ratio, the tensile strength σ_b and elongation δ increase, especially the elongation δ increases greatly. When Fe/Mn ratio decreases from 2.5 to 1, the δ increases from 1.2% to 1.9% by 58%.
By using ICP spectroscopy, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction, SEM and microscope analysis, the effects of Mn on the structure of B319 aluminum alloy are studied. The results show that without the addition of Mn, there are coral-like Al_2Cu phase and needle-like β-Fe (Al_5FeSi)in the structure of casting with lost foam casting (LFC). Precipitation of Al_2Cu can take place along the long sides of the β needles. Under the rapid cooling rates, such as ones in metallic mold, the Fe phase appears in the form of Chinese script α-Fe. With the addition of Mn, there are Chinese script α-Fe phases(Al_(15) (Mn, Fe)_3Si_2)in the structure of LFC casting. When Fe/Mn≤1.5, the needle-like β-Fe phases transform to Chinese script α-Fe completely. With the decrease of Fe/Mn ratio, the tensile strength σ_b and elongation δ increase, especially the elongation δ increases greatly. When Fe/Mn ratio decreases from 2.5 to 1, the δ increases from 1.2% to 1.9% by 58%.
