Friction Stir Processing: A New Grain Refinement Technique to Achieve High Strain Rate Superplasticity in Commercial Alloys


Friction stir processing is a new thermo-mechanical processing technique that leads to a microstructure amenable for high strain rate superplasticity in commercial aluminum alloys. Friction stirring produces a combination of very fine grain size and high grain boundary misorientation angles. Preliminary results on a 7075 Al demonstrate high strain rate superplasticity in the temperature range of 430-510 °C. For example, an elongation of >1000 % was observed at 490 °C and 1x10-2 s-1. This demonstrates a new possibility to economically obtain a superplastic microstructure in commercial aluminum alloys. Based on these results, a three-step manufacturing process to fabricate complex shaped components can be envisaged: cast sheet or hot-pressed powder metallurgy sheet + friction stir processing + superplastic forging or forming.


Materials Science and Engineering

Keywords and Phrases

Aluminium alloys; Friction stir processing; Grain misorientation; Grain refinement; High strain rate superplasticity

International Standard Serial Number (ISSN)

1662-9752; 0255-5476

Document Type

Article - Conference proceedings

Document Version


File Type





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Publication Date

01 Jan 2001