Multiple extrusion of Al–4Mg–1Zr (wt.%) is presented as a severe plastic deformation technique to develop an ultra-fine grained material, using rapidly solidified needles as a feedstock. After each extrusion pass the microstructure is refined, the primary Al3Zr precipitates are broken down and <50-nm-scale cubic Al3Zr are precipitated from solution. Recovery dominates the initial passes with recrystallisation becoming dominant during later passes, but the grains remain at the sub-View the MathML sourcem scale. Interestingly, the yield stress and the ultimate strength increased significantly after the first pass, and then decreased – any strength increment gained from the grain refinement was offset by coarsening of the metastable nano-scale Al3Zr dispersoids.
- Aluminium alloys
- Thermomechanical processing
Garcia, D. A., Dye, D., Jackson, M., Grimes, R., & Dashwood, R. J. (2010). Development of microstructure and properties during the multiple extrusion and consolidation of Al-4Mg-1Zr. Materials Science and Engineering A, 527(15), 3358-3364. https://doi.org/10.1016/j.msea.2010.01.030