TWI

The use of friction stir processing (FSP), a process derived from friction stir welding, to tailor a material's microstructure locally to achieve maximum performance was investigated. Superplastic behaviour was examined in friction stir processed 5 mm thickness aluminium alloy 7075. Strain rate sensitivity and flow stress were evaluated as a function of temperature, strain rate, accumulated strain, grain size and hydrostatic pressure. Cavitation associated with superplastic extension was examined by measuring density. A fine grain microstructure was obtained in 5 mm 7075 aluminium alloys via FSP. The formation of cavitation was suppressed by the application of hydrostatic pressure.

3rd International Symposium, 27-28 Sep 2001, Session 6: Metallurgy, Paper 01