Al - 1.04 Mg - 0.85 - Si Alloy Hot Deformation Behavior And Organization, Performance Study

In this paper, in order to improve the processing properties of the alloy and reduce production costs, the alloy composition has been optimized on basis of Al-Mg-Si alloy, mainly based on the6061alloy to design Al-1.04Mg-0.85Si aluminum alloy by reduing Cu content and adding elements of Mn, On Zn. The homogenization process of Al-1.04Mg-0.85Si aluminum alloy was studied. Hot-compression tests of the alloy was carried out using hot compression simulation experiment, the processing map of Al-1.04Mg-0.85Si aluminum alloy was established and analysed. Through intergranular corrosion and polarization curve test,the influence of heat hreatment on the alloy microstructure、 mechanical properties and corrosion was further explored by using Optical Microscopy, Scanning Electron Microscope, Transmission Electron Microscope. The conclusions are summarized as follows:（1） The over-burnt temperature of this alloy is574.5℃,and the proper homogenization condition process for Al-1.04Mg-0.85Si-0.018Cu aluminum alloy is （550℃,24h）. After homogenization, non-equilibrium low-melting point eutectic structure and Mg2Si phase basically dissolve into matrix, someβ-Al5FeSi phase in the grain boundary is transformed into a-Al8Fe2Si phase.（2） The flow stress of Al-l.04Mg-0.85Si aluminum alloy for hot deformation increases with the increasing of strain rate and decreasing of deformation temperature. The value of hot deformation activation energy on aluminium alloy is170.878kJ/mol,and the flow stress can be described with the following equation:（3） The dynamic recovery of the alloy mainly occurs in a region at temperature of320-400癈and stain rates of0.001-0.005s-l,with a peak efficiency of27%.The instability district of the alloy occurs in a region at temperature of310-390癈and stain rates of0.01-10s"1.Processing should be avoided in the instability district. （4） The best heat treatment parameter:solution at540℃for45minutes, water-quenched, then aging at165℃for9hours. On this heat treatment system, the corresponding mechanical properties:σ_b is305MPa, σ_0.2is276.7MPa,δis16.2%.（5） The alloy has obvious intergranular corrosion tendency.On the peak-aged condition,the alloy corrosion is the most severe.On the overaged,the intergranular corrosion of the alloy is low,and the intergranular corrosion of the alloy is not obvious on the underaged.