Study On The Characterization Of Microstructure Of High-purity3003Alloy In Casting And Homogenizing

:The microstructure in different locations about ingots and homogenization samples of high pure3003aluminum alloy have been investigated by using OM, SEM, TEM and EDS techniques, which reveals the inhomogeneity of ingots structure and the main component of alloy compounds. The Homogenizing treatment, including the influence of heating temperature and time, is studied systematically. After further analysis the conclusions come as follow:(1) After the semicontinuous casting, the grain size and uniformity vary in different positions of3003alloy cross-sectional ingots. The grain size is relatively small on the edge and coarse on the center, at the same time some overwhelmingly coarsing grain is observed.(2) The spot and herringbone structure eutectic compounds concentrate on the grain boundary within3003alloy ingots, while the center part ingots gather more herringbone structure compounds on the grain boundary man the edge part ingots. These alloy compounds consist of the Al(Mn, Fe) and Al(Mn, Fe, Si) phase.(3) The eutectic compounds of round ingots from10T production line are Slender boned segregation along the grain boundary, while the corresponding one under30T condition are spot and block shape. And the dendritic and composition segregation are more serious in30T ingots.(4) The grain segregation especially the Mn segregation almost disappears, after the homogenization process, the homogenization temperature and time do not affect the grain size obviously, with abnormal grain growth occouring. Also the intermetallic compound after homogenization dissolves but not eliminates totally.(5)The inside structure of the grain assembles with the structure of metastable state in single phase solid solution ingots. After homogenized at595℃/13h process, the solid solution precipitates numerous Al6(Fe, Mn)phase. when the temperature increases to605℃, partial tiny Al6(Fe, Mn) phase dissolves although the coarse Al6(Fe, Mn) phase remains.(6)The optimizational homogenization of3003alloy cast is605℃/13h under production condition.