Effect of layered microstructure on superplastic forming property of AA8090 Al–Li alloy

Deformation Behavior of Inhomogeneous Layered Microstructure

“…Higher elongation to failure in 78% fine grain material can be attributed to concomitant microstructural evolution and increase in m value with strain. Comparison with previous work on Al-Li 8090 alloy [1][2][3] and Al 5086 alloy [4] with present work brings out the fact that to observe better superplasticity in a material with inhomogeneous microstructure the proportion of fine grain microstructure should be equal to more than 50%.…”

“…However in recent years, work on Al-Li 8090 alloy [1] and, FSPed material having inhomogeneous layered microstructure containing coarse and fine grain microstructures have shown significant higher ductility then uniform fine grain microstructure [2]. In Al-Li 8090 alloy better superplastic properties were reported by Fan et al [1] for sheet having 67% fine grain microstructure whereas, Pancholi and Kashyap [3] showed better superplastic forming properties in 50% fine grain microstructure. In another work on Al 5086 alloy, wherein inhomogeneous microstructure (50% fine grain) was introduced by FSP, higher ductility was reported in the sheet having inhomogeneous layered microstructure than the sheet having 100% fine grain microstructure [4].…”

Effect of microstructural inhomogeneity on superplastic behaviour of multipass friction stir processed aluminium alloy

“…The work by Snyder et al [13] on superplasticity in a laminated composite between non-superplastic interstitial free iron (IF) and superplastic ultra-high carbon steel (UHC) showed averaging of the individual material properties for the composite material. However, microstructurally inhomogeneous materials (i.e., Al-Li alloy) exhibiting concomitant microstructural evolution do not follow this rule [14,15]. In present work, considerable microstructural evolution was observed after deformation of the NL and CL.…”

Effect of Different Proportion of Coarse and Fine Grain Microstructure on Superplastic Forming Characteristics

“…For a bulge with uniform thickness, values of thinning factor should be one from edge to apex and slope of the best fit line as zero. Therefore, any deviation from the ideal condition can be characterized using slope of the linear best fit line to the data of thinning factor [10], [14]. From Fig.…”

“…Some work on reduction in thickness variation through microstructural control has been introduced and studied recently [9]- [13]. Work on Al-Li 8090 [14], FSPed Al 5086 [10] showed that sheet having inhomogeneous microstructure (coarse/fine) exhibit lower thickness variation than the sheet containing uniform microstructure either coarse or fine. However, there is no systematic study on effect of relative proportions of coarse and fine grain microstructure on thickness variation.…”