The Effect Of Pb And RE On Microstructure And Properties Of Mg-Al Alloy

Mg-Pb alloy has solid solution but there is few research about it .RE can improve heat-resistant property of magnesium alloy.The compound RE-Al that has the high melting point and hot stability is a strengthening phase.Adding different quantity of Pb and RE to AZ91 or AZ61 is studied in the paper by using measurements of Optical Microstructure(OM), X-ray Diffraction(XRD), Scan Electric Microscopy(SEM), microcosmic hardness and impact toughness.The result of experiments show that :1) Addition of a small quantity Pb can clealy suppresses the precipitation ofβ-Mg₁₇Al₁₂ and the diffusion of Mg and Al atoms.2) RE can refine Mg-Al alloy's grain size.The hardness of Mg-Al alloys is improved after solid solution treatment (350℃×10min and 420℃×10min) and aging treatment (200℃and 120℃) and it is found that Pb can retard the time of precipitate .The experiment of Mg-Al alloys in the solution of 5%NaCl shows that the addition of excessive Pb can decrease corrosion resistance property and RE can enhance corrosion resistance remarkly.At last the flame-retarded property of Mg-Al alloys was studied.The result shows that Pb has a disadvantageous effect on burning point of Mg-Al alloy.The more the concent of Pb, the lower burning temperature is . A blend of RE can obviously improve the burning temperature obviously.