Development of Superplastic Properties in Quasi Single Phase Alloys

Roger Grimes; R.J. Dashwood; A. Dorban; Martin Jackson; S. Katsas; I. Pong; G. Todd

doi:10.4028/www.scientific.net/MSF.551-552.357

Paper Titles

First-Principles Calculations of Grain Boundary-Surface for Various Grain Boundaries with Different Energies in Aluminum
p.331

Analysis of the Behavior of a Clad Material Al-Zinag-Al
p.337

The Activation Energy of Superplastic Flow above the Critical Temperature for Steel CrWMn
p.341

Scale Effects in the High Temperature Gas Pressure Forming of Electrodeposited Fine-Grained Copper Thin Sheet
p.347

Development of Superplastic Properties in Quasi Single Phase Alloys
p.357

High-Temperature Deformation Behavior of ELI Grade Ti-6Al-4V Alloy with Martensite Microstructure
p.365

Superplasticity in CP-Titanium Alloys
p.373

Microstructure Evolution of the Ti-6.62Al-5.14Sn-1.82Zr Alloy in the Superplastic Compression
p.379

The Effects of Extrusion Ratio and Friction on Material Microstructures during Sandglass Extrusion Process
p.383

HomeMaterials Science ForumMaterials Science Forum Vols. 551-552Development of Superplastic Properties in Quasi...

Development of Superplastic Properties in Quasi Single Phase Alloys

Abstract:

The early view of superplasticity was that it was a phenomenon that could only be exhibited by fine grained, two phase alloys. This effectively ruled out most alloys that possessed attractive service properties. The first material to demonstrate good superplastic properties from a virtually single phase microstructure was the Al-6%Cu-0.5%Zr, AA 2004 but this was followed by superplastic versions of AA7475, AA8090 and AA5083. Superplasticity was also demonstrated in magnesium based alloys at an early stage. More recently different grain control additions, such as scandium or erbium have been investigated and it has also been demonstrated that, in certain circumstances, aluminium simply with the addition of a grain controlling element can exhibit good superplastic behaviour. While conventional wisdom teaches that large fabricating strains are required to confer good superplastic properties in the sheet product, recent results with both aluminium and magnesium alloys cast doubt on this belief. Although, for many years, strip casting has appeared to provide an attractive semi-fabricating route for superplastic sheet problems with centre line segregation in alloys with a wide freezing range have precluded its use. It has been demonstrated that recent developments in strip casting enable production of alloys with as wide a freezing range as AA5182 to be cast with a fine, equiaxed grain structure across the strip thickness. The paper will review the state of these various developments and their implications for the manufacture of superplastic sheet materials.