The influence of grain junctions and boundaries on superplastic deformation

摘要: Abstract The crystallography of the grain boundary/grain junction network has been analysed in an aluminium—lithium alloy after 1100% superplastic deformation. junctions were classified as “I-lines” or “U-lines” defined by extension to O-lattice model. Overall there 38% I-lines sample population which compares a predicted 4% for random generation. It was shown that orientation distribution alone not responsible high proportion I-lines. occurrence intergranular cavities microstructure associated with angle boundaries and U-lines. Cavities arrested at I-lines, highlights structural differences between two types. With regard mechanisms flow, it argued recognised competing accommodation, diffusion creep dislocation creep, are U- respectively, accounts observed proportions these defects.